Well, I can tell you that I have a time-of-use meter hooked up to the fancy charger that came with my wife’s Rav4 Electric. Does that help?

Unfortunately this has nothing to do with the origional blog post, but is more an idea I had that someone who thought up an electric car, as Mr. Eberhard did, would appreciate and consider. Since I could not find an email address for you Mr. Eberhard, I decided to post in your blog.

Dear Mr. Eberhard,

I am writing you this short blip as an idea to put your technologies to further use. I am not sure how you or someone you sold the technology to would do it, but I would be VERY interested in seeing your technology put into a boat. The scenerio, my family owns a cabin in Minnesota and we have an open bow 17′ boat that we ski and tube behind. Every weekend we go up there an duse the thing all weekend, we are spending well over $100 a weekend on gas for it. Boats like ours for pleasure and watersports are TERRIBLE on consumption of gasoline. Ours only has a 140 hp 4-cylinder engine in it, and since you built a sports car that uses a 240 hp electric motor in it, my thought is why can’t you do the same for a boat. It would actualyl be better for an inboard/outboard application to since the motor would not have to be spinning when you are engaging forward and reverse thrust thus lowering the wear and tear on the lower unit that houses the gears making forard and reverse possible.

Now as for chargin the boat, you could have the charging base station up on land and then have a waterproof cable run along a dok to where you normally park the boat. Put the battery pack in the bottom of the boat and spread it out some and then waterseal it as well. You could also have a boat lift with solar cells on the top of it that could charge your batteries during the week when you are not using it. THen you get to run it down without even having to pay for electricity it took to charge the thing that week.

Unfortunately I am in no position to purchase your technology for that use and start up the manufacturing of such watercraft (if I won the lottery, then maybe we could start talking). I urge you to consider it and maybe even talk with companies like MerCruiser, Glastron, Bayliner, Volvo Penta, all those that deal with boats and share my idea with them. It is all just another step to lower the use of gasoline engines.

Thank you for your time.

Sincerily,

Stephen

Being an electrical contractor the real question would be the figures that the local utility has used to feed the neighborhood. This won’t be an issue when only a few have electrical vehicles, but will come into play when they become a standard item. From what I understand some areas are already near the top end of their load capacity at times because of the increase in power consuming devices in the average house. Remember that many old houses only had a thirty or sixty amp service. Distributed power generation from solar and wind would help solve this problem.

Unlike most houses, my peak demand is at night in the winter. This is because I have a heat pump. But, replacing the resistive furnace (120 amps @ 240 volts) with the heat pump (20 amps @ 240 volts) freed up a lot of capacity. I currently have 80 amps @240 volts available in my garage. 50 amps of that is an RV circuit. I just got rid of the RV, so when is the White Star hitting the market?

It will be interesting to see the statistics showing the percent of those who will need significant electric service upgrades to support fast charging.
I’m sure many who have been postponing electric upgrades on their homes will use the charger installation as an opportunity/excuse to finally get them.

To simplify the customer experience with fast chargers, I’d suggest Tesla do the following:

- Certainly support automatic time shifting of fast charger use to midnight hours.

- Build in a few hundred dollars into the home charger option for a home consulting visit from a Tesla electrical expert (before electric upgrades and charger installation). The expert can outline electric upgrade options, especially if both a Roadster and a White Star purchase are planned.

- Employ or contract with specific electricians in your service area. They can not only install the fast charger, but provide upgrades where needed
to 200 Amp service. Elon’s “Solar City” connection might be a good resource to exploit.

- Compile an list of electrical contractor’s that Tesla owner’s have used and recommend.

- Explain to the Tesla buyer the net metering options such as double metering that some utilities offer. One of the meters provides special electric rates
for electric car owners. Recommended electricians experienced with this type of installation.

- Promote tax legislation such as tax forgiveness for electrical upgrades needed to support fast chargers. (as is currently done for solar panels
in California).

I assume most homes will need some upgrades, but the cost should be modest ($3,000-$5,000).

My home has 100 Amp service that would need to be upgraded to 200 Amps to support the assumed 70 Amp fast charger current draw.
When the girls at home turn on their hair blowers, the 100 Amp service is not enough even now.

I unprotected the spreadsheet (Tools > Protection). Thank you for not password-protecting the spreadsheet.

I see that in order to get column entries to light up in the right column, we have to put data in the left column. My bad.

I changed the Electric Heater circuit entry for “pool” to “water”.

How do we get these spreadsheets back to you as feedback?

—

Editor’s response: Thanks for trying out the spreadsheet! Martin is looking for two numbers: your available ampacity and the required ampacity for your house as it is now. Please report them as a blog post, along with any feedback about the spreadsheet. (Review the “here is what I want from you” section of the blog, if you have additional questions.) If Martin has feedback to offer, I expect he’ll chime in here as well. (Martin added an electric water heater entry as a result of your feedback. It is in version 1.2 of the spreadsheet.)

For me it is 100 amp service. 14A free and 86 used. However if you look at the exclusions it would be rare for me to hit 5 major loads if I had a roadster charging in the garage. For example if I cook dinner, have clothes in the dryer, air conditioner and forced air furnace accompanying car charger. I had to guess for some of the appliances because there was no readily visible plate or sticker they weren’t on wheels. If I guessed I made sure to guess high. Not very scientific, but the best I can do at the moment.

I think people should also remember all the phantom loads in their homes - all those clock radios, stove clocks, instant on electronics, phone chargers and other consumers. If you don’t put them on kill switches they might add up to an amp or more. I know I was shocked when I realized how many of these devices I had around my own house. It may not help a great deal with the Fast Charger, but I know I shaved a few KWh off my electric bill by using some power bars I already had lying around.

To Strada - All new houses I have seen in Southern Ontario have 100 amp service. I have lived in two new houses in the Toronto area (905 belt) in the last 10 years. Both builders only installed 100A service and insisted I would never need more. Where have we heard similar statements in the technology industry?

One question - If someone has a solar installation is there any way to charge the car batteries directly from the DC power of the panels? There are losses converting the DC power from the panels to AC and I assume the car’s charger is also not 100% efficient. For the amount of power we are talking about even a couple percentage points would affect the number of panels. Hmmm, actually going 100% solar to charge a roadster anywhere in the Great Lakes region would require an awful lot of panels - surely more than I could afford, especially on the winter solstice

Chris,
We are in 905, and in our neighborhood the homes have 200, you might have a point that builders would have gone to 100 in a cost saving measure. Builders and electrical contractors leave little room for expansion in the circuit breaker boxes that come standard in home or industrial applications. In an industrial application we have had to install an additional breaker box to accomodate additional circuits for lack of room in the existing breaker boxes.

If the Tesla fast charger requires 70 amps most private homes would be challenged to accomodate that level of amps, as an addition to the existing requirement of the home. Ideally the Tesla charger should not use more amps than a major appliance (electric range, clothes dryer, a/c) and it would charge at night.

Using the spreadsheet, my 200Amp service has a connected load of 177Amps and an available capacity of 23 Amps.
This is a fully loaded service when everything is on. This is almost never the case. A charging system is a “continuous load, more than three hours at a time” and must be circuited accordingly. Article 625 of the 2005 NEC also has requirements for vehicle charging systems. As an electrician, I am looking forward to all of the new work associated with electric vehicles. As you mentioned, control systems which create non-coincident loads are probably the least expensive method to create capacity for a vehicle charging system.

Martin: I believe what you are looking for is the electrical amperage ‘headroom’ available for charging a car at my home. In my case, getting my usage number tracking down a circuit at a time will be problematic and error-prone. Could I suggest we use our electrical watt-hour meters to derive the actual usage. This would be a lot simpler and would include ALL loads. In my case, I would take a reading at 11:00 pm and then at 5:00 am (what we dedicated Tesla-ites will do knows no bounds). I would then subtract the two readings, divide by 6 to get KW’s, multiply by 1000 to get W’s and then divide by 240 (my meter measures at 240v) to get Amps. This would certainly be an average number over those 6 hours and would not include transient spikes when things like Air Conditioners switch on. Nonetheless I think I could get a better number this way and it would certainly be easier – except for the 5 am part.

Would this meet your needs?

Harley Dave

—

Martin says: No - The purpose of this exercise is not to measure *actual* headroom at all. Rather, it is to understand the code requirements for installation of an EV charging system in your home. When your electrician goes to pull a permit with your local building department, the building department will not be interested in your power meter measurements - they are building inspectors, after all. They care in a very single-minded way what, exactly, is the letter of the applicable building code - the electrical code in this case. My spreadsheet (and the work you need to do to fill out the spreadsheet) exactly interprets the applicable sections of the National Electrical Code to determine how much additional load the building department will allow you to add to your existing service.

You might argue that, even though my spreadsheet (and therefore the NEC) say that you don’t have enough headroom, you actually do, because many of your loads are not on at the same time. You would then need to demonstrate that you qualify for exemption through paragraph 220.60 (Noncoincident Loads), as transcribed above.

You might also argue that my spreadsheet (and therefore the NEC) says that you do have enough headroom when you in fact don’t (perhaps because of your fabulous collection of 1,000 vacuum tube clock radios that run all the time and are not accounted for in the NEC rules). This is your own judgment call - you can choose to upgrade your service if you want. Nothing dangerous will happen if you don’t - but you will trip your main breaker if your car starts charging when you have everything else on. But this is not an issue for your building department.

Note that some localities choose to add additional requirements above and beyond the NEC. This is getting to be more and more unusual in the US - there is a strong trend here toward uniformity of codes. But obviously, my spreadsheet cannot take into account local code differences.

Guess the NEC code is par for the course-try reading certain sections of the IBC for “more fun” (not). If you want to do a building with an enclosed atrium, some mech. engineers will decline to do the job because of all the mumbo jumbo involved. My Tesla power solution will definitely, no question , be those approx. 10′ x10′ solar panels via Solar City, or others. I’ll leave car home one day (at least)for charging purposes. Tesla should provide solar system with car purchase for as cheap as you can, as an added incentive.

Spreadsheet (v1.2) result: total required 143, available ampacity 57. This includes a phantom load of 24 A for an electric dryer (we use propane).

Location: San Carlos, CA
Service : 200 Amps
Required ampacity: 113A
Available ampacity: 87A

I got the power. Now all I need is 100Gs!

—

Editor’s note: Thanks for including your location!

Just a note—you need to add an option that says something like: “cannot change electrical wiring because I live in an apartment” (that would be my situation).

I think this will be something that EV vehicle companies will have to anticipate/address in some way as they roll out this new technology more widely.

I think you’ll need a lower amperage station. Although 200 & 250 amp services are common, they tend to be on all electric homes. For me, the difference between a 3 hour charge and an 8 hour charge is meaningless. I get home, plug it in and unplug when I leave in the morning. Needing more than a half charge would be a rare event, 95% of my trips are under 80 miles. Actually, I can probably get by on the 15 amp/120 volt travel charger.

[Just a note to people: If you have two breakers connected by a bar, it is likely that each breaker is only 120 volts and interrupts one side of the 240.]

# Editor’s comment: Thanks for the update, TEG. Martin is looking for both the “required” number and the “available” number.

If I leave off the existing 32A Avcon, then I have 51A required, 49A available…
(My range, water heater, and dryer are all gas so I don’t have those as load items)

Martin: Got it. Sorry about that. The number you’re looking for is (A), that allowed by the building inspector. The number I was producing is (B), that allowed by my main breaker. I’m actually going to do both. If (A) is less than (B) then everything’s OK. If (A) is greater than (B) I could start popping breakers. So I really want min(A,B).

SPREADSHEET GLICH(V1.2): Central Vacs. Every entry in Step 2 generates one or more entries in Step 3…except Central Vacs. Enter (1) for Central Vacs in Step 2 and nothing appears in Step 3. The answer at the top tells me “step 3 incomplete” when I’m not being allowed to complete it. I’ve unlocked the spreadsheet and can fix it myself, but I think I should wait for official update.

—

Editor’s comment. You are right! Martin has updated the spreadsheet.  Look for version 1.3. (Version number is at the bottom, left of the spreadsheet.) If you don’t see version 1.3, clear your browser cache. (If you need help clearing your cache, here is a good resource.)

Martin says:

“1) How many houses can actually support a 70-amp charge? Would it be worthwhile for us to create a less expensive, lower amperage charging unit for your garage.”

I don’t mean to undermine you, but I want to point something out just in case by some chance, you missed this.

The people who are buying the Roadster (obviously) have cash, and I’m sure they’ll spend some cash to upgrade their wiring in their house if needed/wanted.

Unless the charger is going to be of use by your future vehicles, why clamor over a charger that’ll only have problems with maybe a couple of your customers. (or “members”) And the only “problem” is that they wouldn’t be able to cahrge quickly, so really, what is the problem then?

Of course, if the charger is going to be in use for your future vehicles, ro if you think it’s worth the possible cost reduction, then it’d make sense. You’re the boss! I’ll be posting soon the info.

Total required ampacity for 240V 1-phase Main Electrical Service 120 A
Available ampacity in Main Electrical Service 80 A

Hey guys, thanks for the spreadsheet; I needed to figure out how my loads were doing anyway! I’m just about to start, so I’ll report back soon, though I’m positive it’ll be way low…of course, I’m well below the income level of your potential customers anyhow. (Don’t you think a full survey that asked a few more questions about income, current vehicle cost, and maybe home age/value might be more worthwhile? This seems kind of like shooting from the hip here…)

Anyway, just dropped in to wonder about the feasibility of a “dump charger” arrangement. If I were to stack up 50kWh worth of lead-acid batteries in my garage and let them charge overnight at 6kW or so (on a 30A 220V breaker) or all day/night at 2kW (on a 10A), how fast could I dump this into the roadster? I guess in truth one would probably need somewhat more capacity than that to account for charging inefficiencies and the fact that lead-acid batteries don’t like being run too far down, but you get the point…could a battery-based charging system be an option for those without much headroom in their electrical service? Could it be even faster than the fast-charger? I suppose given any high-voltage-capable dc charging system it would be easy to rig the battery part, so it’s a similar question to the guy looking to do the solar thing.

I’ll get back to you when I’ve finished this spreadsheet…

Required: 135A
Available: -35A
Main: 100A

My electric range, A/C, and dryer apparently use 100A by themselves. I never actually trip the main breaker because the devices never use anything close to the total amps allocated to them.

The “noncoincident load” loophole definitely applies to me, as some of the biggest power hogs (range, dryer) aren’t used overnight. Unfortunately, since I’m already overallocated, I’m not sure if the electric code would allow me to charge at all during the day. But, I’m willing to upgrade to 200A service if an EV needs it

Fascinating car, but I´m missing a few things. First what´s the drag-co of the roadster, can´t find it any where on the website., secondly couldn´t one option be to replace the sidemirrors with small cameras which display it on the central screen to improve the drag-co or is that just hair-splitting?

San Carlos House
————————-
Required - 86A
Available - 64A

Hillsborough House
—————————-
Required - 90A
Available - 110A

Pacifica 4-Plex [where my Roadster funds went for a down-payment]
——————–
Required - 39A
Available - 11A
*** This building has 4 units. Each individual unit has the above results.

I would have ran the numbers for the small industrial building we have (just in case I wanted to make a studio in one of the units) but I don’t think the spreadsheet supports 3-phase.

Can I be in the beta test?

I live in an appartement building in Singapore, as 70-80% of Singapore does. This makes for organised parking lots with substantial power feeds for the appartment building. 2 small problems do present themselves.

The first is pulling together the right support to install the charging stations. Secondly eventhough Singapore is probably the worlds best test ground for electrical cars (city state, with some high ways (max. 90km/hr), limited distance of travel on average, a rich nation (plenty Ferrari, Porsche, Lambo’s), tech savvy, a forward looking decisive government), there are no electric cars (only some hybrids)! When are you coming to Singapore again?

Further I have seen some reports on prototypes from Mitsubishi and Volvo (via www.gizmag.com), they opt for in-wheel electric motors. Having read this blog for some time I was somewhat surprised to see this developments as the arguments against the in-wheel motors seems substantial. Is this window dressing or actually a feasible solution?

Good Luck,
BW

Last year I installed a ground source heat pump and replaced all my gas appliances with high efficiency electrical appliances (such as an induction cooktop), so I made up a similar spreadsheet (not quite as nice, though) based on 220.30.

My sheet:
Required: 143 A
Available: 7 A

Martin’s sheet:
Required: 164 A
Available: -14 A

I need to find the discrepancy. At the time the electrician and inspector agreed with me.

Applying 220.60 to Martin’s sheet, I get:
Required: 111 A
Available: 39 A

The utilities here in MN typically use a load control receiver to control large loads if you want to qualify for interruptable (cheaper) or off-peak (cheapest) rates. The charger would therefore need to be controllable via the low voltage (lt 24 V, lt 1 A) relay in the LCR.

V1.3 working fine. I have 400 amps at the breaker (Power to the People!). Spreadsheet results:

Location: Atlanta
Required Ampacity: 126
Available Ampacity: 274

So much for the Building Inspector. But what am I really using? It better not be anything like 126 amps. Using my watt-hour meter and taking readings at 11:00 pm and 5:00 am, my average usage during the window that I would be charging my car is: 29 amps, which explains why my electric bill isn’t close to the national debt.

The next issue is power utility capacity. Having lived through California brownouts during 10 years in silicon valley, nobody’s breakers were popping, we just didn’t have enough juice from PG&E during hot months when we all had our AC’s running at the same time. If everyone in Atlanta charges their car during the same window and approaches their breaker capacity, we’ll have the same problem here.

Alexmcfire, the Tesla Roadster has a Drag Co. of .30

I think my post of the electrical capacity of my home didn’t get past the editor. I’ll post it again just in case. It was something like…

Required: about 125 ampi

Left over: about 75 amps

I made alot guesses on the power use of the appliances though. I couldn’t find the power use of the appliances on the internet or through the oweners guides. Instead I found websItes that listed the average power use of different appliances and just went along with that.

—

Editor’s note: We published your previous post with results on September 7. 

Required: 204
Available: 200
Its quite a project to find all those numbers on those old nameplates - but it sure was interesting to see just how many things run on electricity in our house. The self-cleaning double oven plus all the cooktop burners really pull a lot of Amps.
Perhaps some sort of a clamp-on current monitor could be put in the main box to continuously measure the current draw and used to control the EV charging rate. This could make sure the full 70Amp charging is only done when the house is not drawing too much - which is probably all the time.

just remember all the people who are waiting impatiently for you to create a more affordable car. I, as one of those people say, if your TESLA can do all this, i’m sure you can make another electric car with 1/3 of power, speed, etc at 1/3 the price….{as long as we can still get that 200+ miles to the charge }

I support your company more than any of the big boys because of your true desire to rid us of our addiction to oil and other fossil fuels…please beat them to the punch and get a more affordable electric car out there…..i will be your first customer.

thank you for letting me post…

As currently configured, I come up with 154A required, 46A available. However, I do have 2 water pump circuits no longer in use, which would bring it to 138/62. If I also removed the 30A garage circuit (originally for an EV), I get 120/80. So with little work I could come up with enough to run the fastest charge even ignoring the concurrent load loophole, but frankly I would probably just stick with the 240V 30A circuit already available as I envision only charging overnight.

Jay

Along with the GM “Volt” trying to take some of Tesla’s thunder, comes the new Volvo “Re-Charge” plug-in series hybrid:
www.autobloggreen.com/2007/09/06/frankfurt-preview-volvo-recharge-the-swedes-go-series-hybrid/

Have you also looked at this online tool?

northwestsolarcenter.org/Resource/loadsize.html

Total required: 181A
Available: 19A
Location: Sumter, SC (in a new subdivision, house is 8 mo. old.)
—–
Comment: Geez, people! The man just wanted a string of replies that read as above. Figures after figures, not all the extraneous comments! (Of course that’s exactly what I’m doing here…)

Location: Sacramento County (SMUD territory)
Residence built 1991
Req’d: 154A Avail: 46A

I like the idea of the concurrent load loophole and believe I would qualify. However, because SMUD offers EV charging at rates 1/2 of regular residential rates, the minimum effort to modify the existing panel to provide for the required new separate meter, I am inclined to go the route of expanding capacity with a completely new panel at a relatively modest additional expense. The incremental effort/expense would therefore provide capacity for the 70A (90A circuit) home charger.

Does anyone know why Ian Wright stopped working at Tesla to start his own venture? Given the history working with Martin before Tesla on conversions I would think that is a natural fit. What did he want to do that he could’t at tesla? If anyone has information on this please post. Thanks!

Maybe I missed it, but why hasn’t anyone mentioned alternative circuits. Up here in Saint Paul, MN, my garage not only has the typical 15A/120v system, but also a dedicated 20A/120v circuit for an air compressor and 60A/240v for an arc welder.
we never use the 20 ampere circuit because frankly, the neighborhood kids think the air compressor will eat them if they cross our lawn. Yes, it really is that scary. My grandfather built it himself, and in the early Seventy’s liability wasn’t an issue. So now, it sits in a dusty corner with its plug removed (for the sake of young children’s’ fingers everywhere).
As for the welder, the last time IT was used was to construct the afore mentioned Digit Dicer.
So, Tesla has many options for charging circuits. I think at least one model of your charger should be capable of 20 amps at 120 volts, because commercial buildings are almost always equipped with 20 amp branch circuits to run those ride-on floor waxers. This way, i could always grab a quick charge during lunch at Tobie’s on my way to go skiing in Duluth ;^}
We should also be able to simply order our chargers with a PLUG for use on the otherwise abandoned welder and/or dryer circuit that resides in so many garages.

I am approaching this from a different angle.

I would rather buy my “gas station” along with my Roadster, and I want it to be solar. My new home will be 100% off the grid with a 5KWH system feeding a small 2.4KHW energy budget. I’d like to charge my car anytime of the day using solar power, but especially during peak sunlight hours.

So, I am simply seeking to design a separate, dedicated solar array around the needs of the car and the garage/apartment/workshop, while not requiring more solar PV panels than the space station. I work at home and will probably only charge the car twice to four times a week. I would sell the excess power to the grid.

I’ve seen 110V and 220V used interchangeably in these posts, but 70A and 110V seems to be mentioned the most frequently.

So, I am thinking a dedicated solar system capable of handling a sustained 7.7+ KW AC load for up to 4 hours is sufficient to charge up the Roadster, and then I’ll add capacity for the garage apartment itself. Correct?

- JonE

Location: Fremont, CA
Service : 100 Amps
Required ampacity: 85A
Available ampacity: 16A

The results from my house (built in the mid 70’s, about 2300 sq ft) indicate that I am using 85 Amps out of the 100 Amps available leaving only 15 Amps (rounding) available for a charger.

For new construction in Oakland county, MI - should you install a heat pump / geo-thermal furnace, DTE Energy insist on 2×200A main panels! The geo, hot water, electric drver etc can run off ‘Time of Day & Electric Vehicle’ meter, which is charged at half the rate of the other 200A service for lighting, cooking etc. Lots of capacity for a 70Amp charging circuit!

jon ellis wrote on September 12th, 2007 at 3:03 am

Jon raises a good guestion:

“I’ve seen 110V and 220V used interchangeably in these posts, but 70A and 110V seems to be mentioned the most frequently.”

I want to make sure I understand the amperage requirement for charging. It comes down to watts and then volts. Assuming I want to fully charge all 50kWH of battery in 6 hours, that will take 8333 watts (50,000 WH/6 H). If this is delivered at 120 volts that works out to 70 Amps. If it’s at 240 volts that’s 35 Amps. So the question: is the charger 240 or 120, or are there two different chargers?

Powering an electric car at $0.16 per kilowatt/hr charging a battery with 35 kw of energy will cost at least $5.60 and this assumes 100 % efficiency and that rates won’t go up, which they are. This gives you enough power to go about a hundred miles. This is puts it in the range of diesels, of which several are currently being produced by BMW, Honda, VW and several others that get around fifty miles per gallon. It looks like a race between diesels powered by algae based biodiesel and pure electrics powered by energy generated from alternative sources. I think the winner will be a diesel serial hybrid wtih batteries giving the vehicle a range of 30 to 60 miles that can be plugged in at night. This solves the problem of range and infastructure. A battery pack that only has to provide a range of 40 miles is almost affordable right now and the costs are coming down and advanced diesels that run at a constant rpm are highly efficient right now and only getting better. A small capacitor for power recovery would make this vehicle extremely efficient.

Location: Waukegan, IL

Service: 200A

Required: 49A

Available: 151A

I should also mention that we are in the Chicago suburbs and that an upgrade to 200 Amps service is available for about $1000. We rarely blow any fuses (yes it’s an actual fuse box ).

With some assumptions, 24 available on a 200 amp panel in Oakland, CA.

That 400 amp panel ain’t cheap, either!

Location: Dayton, OH
Service : 200 Amps
Required ampacity: 126A
Available ampacity: 74A

To TEG2: Natural gas is extremely efficient for heating purposes… but it’s a fossil fuel, so we’ll inevitably hit a supply crunch and, ultimately, depletion.

If you can get natural gas cheaply, by all means stick with it Just save some room in the budget to start switching things to electric in the future

A lot of people are concerned about the extra load EVs will place on the grid, but it’s nothing in comparison to the load that’ll happen when people are forced to start switching their heaters to electric en masse.

martin:

required: 97
available: 3

this is ~25 year old condo in hoboken, new jersey.

one alternative that i have not seen discussed is that the charging station can actually take a charge itself, perhaps using an almost identical battery pack as in the car. this way, the station can charge itself during off-peak hours (or top off more slowly during peak hours if this is desired), and a full charge at the ideal amperage is always at the ready. ironically, certain hybrids work the same way, except the power souce comes form the internal combustion engine rather than the grid. the benefits of this option are that the load on an existing electical system is minimal, the cost to charge is minimized, and the station is always ready to fully charge the car at the ideal rate in the quickest time. the drawbacks are that the station gets larger (must be the size of the battery pack, although the dimensions can be adjusted), and these batteries will require replacement just as those int he car will (in a way it doubles the future battery replacement costs). however, rewiring, etc. may cost upwards of $1k, so this is not as bad as it seems.

~ian

I will be running down all the numbers for my home here in San Mateo, CA this weekend but in the meantime I have one question for you and that is: besides the Whitestar (when will pictures be available?) is there a Tesla pickup truck in development? Maybe I’m wrong but this will be VERY popular with those of us who have pickups and SUVs, not to mention utility fleets. Martin, can you shed any light on this?

I was curious about the charging unit that comes with the Roadster. For those people who install solar panels in their homes and wish to use them to charge the car, does the charger even accept 12V DC, or do you require it go through the lossy conversion to AC just to be converted back to DC by the charging unit ?

One othe note, one of the biproducts from producing biodiesel from algae is the ultra efficient production of large amounts of high protien animal field per acre.

Total required ampacity for 240V 1-phase Main Electrical Service 141 A
Available ampacity in Main Electrical Service 59 A

I ran the spreadsheet with no problems, although time consuming. Home has 300 Amp supply of which 240 is allocated and 60 is free. Our pool heater is a heat pump and tried to enter it under motors but was not permitted to enter 240V. Entered under “pool heater”.

What is availability of A123 technology for Whitestar? Has GM’s reltionship blocked you from access?

HI Martin,

Electrical Main size 100 Amps
Living space 753 sq feet (It’s a small appartment.)
60Amps required 40 Amps spare.
We have gas heating and water and no Air Con which migh explain the apparent large spare capacity.
If Tesla ever comes to Australia you will be on my list for my first\next electric car.
P.S Australia runs on 240 V for everything, not sure if this affects the calculations in your spread sheet.

Would you please advise the minimum power requirement needed for charging the vehicle.

—

Editor’s response: Technically, the Tesla Roadster can be charged off of just about any 110-volt or 220-volt electrical socket in the United States using the optional mobile charging kit. The Home Charging Station can be configured to work with relatively small circuits – less than 20A – but charging times will increase as a result.

Location: Northridge, CA
Service: 100 A @ 240V
Total required ampacity: 67A
Available ampacity: 33A

A couple of comments:

- You might want to clarify whether two joined main breakers labeled “100A” should be input as “100″ in your spreadsheet or “200″. I’m presuming that you want “100″ (ie. the feed is assumed to be 240V). If not, disregard the above numbers, and I’ll repost.
- I’m seriously looking into solar panels to provide some/all of my house power. Unfortunately (for me), from what I’ve read, LADWP was exempted from having to do annualized “net metering”, so instead they only do _daily_ net metering (in other words, if I want to keep my usage from LADWP at 0, I can only use as much power during the night as I’ve fed back into the grid FOR THAT DAY - sheesh!). With that in mind, I think environmentally-conscious LA owners will need a means to limit current drawn for recharging to a quite low amount (ideally, it should be tied to the amount of surplus electricity “given back” to the grid in the past 12 or 24 hours, but that may be difficult to obtain). Of course, this also means that I’ll likely be plugging in almost every night, to “top off”. Hopefully this type of usage won’t adversely affect the useful mileage-life of the batteries.

To answer Martin’s two questions posed above:
1) My house cannot support a 70-amp charge without upgrades. Therefore I’d want/need a lower-amperage (more flexible) charging unit for my garage.

2) Yes, by all means, you should create a “time of use” option (that included an internal clock) for the charging unit that guarantees a lower charge rate during the daytime (when we might be using most of your house’s load), but still allows a decent charge rate at night? Of course, in my case, since I’d be generating excess electricity during the day, I’d want the higher charge during the daytime, and lower at night. Go figure…

Best of luck, and I’m anxiously awaiting the release of specs. for the White Star (and desperately hoping, at 6′5″, I can fit into it, unlike the Roadster).

> TEG2 wrote on September 13th, 2007 at 4:43 am
> How do people feel about this? Are some of you more “pro electric” for appliances than others?
> I tend to think that gas dryers, water heaters, central heat, and stove tops work better than their electric counterparts.

Since this is off-topic, I wanted to reply at teslamotorsclub, but it seems that site has been overcome with porn spam and abandoned.

Before coming to the USA, I had no idea that people living in the city used gas as a household fuel. It seems very dangerous to have open flames inside a house made of wood and paper (instead of brick and cement as I was used to). Every year in Minnesota there are about five cases of exploding homes, or people dying of carbon monoxide poisoning that make it onto the news. Who knows how many more gas related fires go unreported.

I wanted to switch to all-electric for years now, and the opportunity finally came last year when my A/C broke down. I replaced the A/C and gas furnace with a Hydron-Module ground source heat pump, the gas water heater with a Marathon unit and the gas stove with a Sears induction cooktop. I already had an electric clothes dryer.

This gave me higher energy efficiency, greater convenience, and of course, safety:
Heat pump:
Efficiency: Measured COP gt 3.0 in February, better in warmer months. (Old furnace COP was 0.8)
Convenience: Less maintenance than gas furnace and outdoor compressor.
Safety: Zero risk of gas explosion or CO poisoning.

Water heater:
Efficiency: Published EF = 0.93, measured EF = 0.98. Compare to best gas heaters at 0.86. (Old heater was 0.64)
Convenience: No more loud popping noises as water heats up. No more birds getting trapped inside the chimney.
Safety: Zero risk of gas explosion or CO poisoning. No more birds getting trapped inside the chimney.

Induction cooktop:
Efficiency: It cooks the food, not the house, therefore less heat to be removed in summer. Typical EF around 0.84 compared to gas at 0.4.
Convenience: Much faster and more controlled cooking. Less heat in the kitchen.
Safety: Zero risk of gas explosion or CO poisoning. Zero risk of rags or paper towels left too close to the stove catching on fire.

To paraphrase Martin: To hell with gas!

While with the Tesla roadster home charging will be sufficient I would suggest that with Whitestar you will need an option of on board charging to extend range. Can I suggest you invetigate the use of the Freedom Motors compond Wankel engine, (see www.moller.com/files/Rotapac_Power_Module.pdf ). This engine has a theoretical efficiency as good as a diesel, and is extremely light and compact. It also has the advantage that it runs very cleanly on ethanol, and particularly so when the ethanol has around 20% water content. This is important as removing water to get pure ethanol is expensive and energy consuming.

A Whitestar with an on board charging runnning on ethanol/water will completely preserve your “green” credentials, and allow Tesla owners continued independence from imported oil.

Location: Portland OR
Required 174A
Available 26A

I have an all electric house. I won’t get away with 220.60 automatically. I have energy storage heaters so I’m already pulling (up to) 13 KW in the middle of the night in the winter for heating the house. So if I’m cleaning the oven at night and the hot tub heater and hot water heater kick in, I am actually fairly close to that 174A number… Now if the charger doesn’t mind losing it’s power until the storage heaters have gotten their fill, it could be connected to a load management system relay and everything would be fine… (In other words, a battery backup on the clock and settings on the charger would be a good feature. Even better would be a control wire interface of some sort.)

J in MN wrote :

“Since this is off-topic, I wanted to reply at teslamotorsclub, but it seems that site has been overcome with porn spam and abandoned.”

The Tesla Motors Club has moved to it’s sister site here: www.electricperformance.com/

I am running the same gas VS Electric household numbers as I consider a very large PV/Wind system. For cooking there is no question. Ask any chef and you will find that gas is clearly the way to go.

Also I would worry just as much about an electrical fire as I would a being gassed or in a gas explosion. I’d bet the Fire Dept. would say they see more of the former.

I can’t directly answer the original question, which I suggest you ask at an electrician’s forums, like Mike Holt or Electrical Contractor Network. They know the NEC and every loophole.

What I can add is some information which I think Tesla could be interested in:

The amount of power available in a domestic service varies between countries. This also leads to limitations in different parts of the system, depending on how the system is laid out.

As you already know: In North America a typical service is center tapped single phase: 120/240V at 100 or 200A. This gives you 24 kVA or 48 kVA maximum, minus the 80% rule. Martin has already laid this out above.

In Europe a typical service is either single phase 230V (UK, Ireland, France etc.) at 40 - 100 A or three phase at 230/400V (Germany, Denmark, Sweden etc.) at 25 - 63 A per phase. There is no 80% rule and usually nothing in the rules to prevent you from loading this to 100%. Actual measured load. This means the power available at the house is typically anywhere from 9 to 45 kVA. (Smaller services do exist but any customer who can afford the Tesla Roadster is unlikely to have a very small service.)

Some countries (e.g. Israel) make the smaller services single phase and all larger (25 A and up) three phase.

As the alert reader may already have figured out is that homes with the power split over three phases imposes a severe limit on the charging of the Tesla Roadster: With a charging voltage of 220-240V it needs to be connected phase-neutral. This means you can only use one phase. This in turn limits you to 25 - 63 A at 230V which equals 6 - 14 kVA.

In Japan, power is supplied at 100V only service in many locations, with 200V also available in more recent homes. Similar to the North American system, but also available as a centre tapped delta. (A three phase system with 100 V neutral to phase and 200 V phase to phase.) The amount of power available is quite limited.

It is possible to design a simple and inexpensive system that allows the vechicle to work in all countries, optimised for the available power and meeting all safety requirements. Should Tesla be interested in this, send me an e-mail.

vfx wrote :
> The Tesla Motors Club has moved to it’s sister site here: www.electricperformance.com/

I’ve tried several DNServers, but this URL does not resolve.

> For cooking there is no question. Ask any chef and you will find that gas is clearly the way to go.

I have yet to meet or hear of anyone who actually tried induction and did not agree that it is better than gas. Like so many other things, the inferior/conventional/familiar technology is perpetuated, because people simply don’t want to be bothered with trying the superior/new/unfamiliar technology. (Not that induction is new - it’s been around for decades in Europe and Africa.)

> Roger Anderson wrote on September 15th, 2007 at 12:33 pm
> A significant opportunity exists in the sailboat re-power market.

while i don’t know if jumping into this is as easy as suggested, i totally agree that this is an excellent sister application of the technology tesla is developing. many new sailboats are being constructed right now with hybrid systems (larger than typical genset also charges battery pack that powers silent, clean, efficient, and more controllable electric motor driven prop(s). it’s clear that this is the future of sail-boating (and eventually powerboating), and retrofitting (or providing kits for) existing boats with aging diesels is a significant, untapped market. as roger anderson mentioned, most sailboats are already conveniently wired with an existing electrical system which typically includes an a/c shorepower hook-up, so this application is that much less challenging.

interestingingly, i have not seen any of the new hybrid designs substitute the traditional lead ballast in sailboat keels with an active battery pack. i imagine the weights are similar, and while this location would be more difficult to access and require a more vertical battery pack design, it doubles the utility of the weight of the ballast necessary in a sailboat’s keel.

it’s good to see that full size cars will soon be on the streets more often. i have had been into racing electric powered 1/10 model cars int the past and have always imagined how it would be a great idea to make a full size car into electric. i guess i was one of those only kept the thought in my mind only and did nothing about it. well now i have the opportunity to type something about it :
i’m pretty sure there are millions of ideas to improve the capacity and charging methods of tesla cars i still want to add a few more: front tires can be loaded with hub style dynamos to produce electric to recharge the batteries on the fly, front air intake can be equipped with a dynamo-fan system that would generate enough current to recharge batteries via wind power, solar panel can be embeded into the hardtop of the car for maximum exposure to the sunlight to generate extra energy for recharging batteries, couple of Faraday’s Magnetic Field Induction coil can be installed into the various locations of the chasis to generate energy from the momentum of the car, (also this can be applied to inside of the wheels if there can be a way to do it without unbalancing the wheel), main shaft of the electric motor can be used as an armature of the dynamo to produce current from the motion of the original motor thus causing instant recycling of the energy, battery housing can be cooled via a radiator system that runs with a coolant liquid in it to ensure certain level of temperature constantly cools of the batteries. since electric powered vehicles are made to save our planet i’m willing to produce more ideas about them in the near future and i hope everybody will be able to read all of this thanks.

Clas-Henrik Gustafsson wrote on September 20
It is possible to design a simple and inexpensive system that allows the vechicle to work in all countries, optimised for the available power and meeting all safety requirements.

I imagine the most difficult part would be to meet all the various electrical codes and safety requirements, not because they would be hard, just different. It is trivial to substitute the full wave single phase bridge rectifier with a 3 phase version, so that part of it would be easy.

Dear Editor, My question related not to the amps and voltage required for the charger, but to the actual power draw in watts that the charger consumes to charge the Tesla and how far it will travel on this charge. This will give the readers an idea of the efficiency of the charging operation through the charger and the efficiency of the batteries at taking the charge. I know these figures can vary depending on the charger, the speed of the charge and discharge rate. This is why I suggested a mix of battery types and maybe a capacitor in the mix. Do you have any views or comments on the firefly battery that is coming out soon. It’s set to apear on a Husqavarna product this year. It seams this would offer a low cost alternative until better low cost batteries come to market. Thank You

Hi, Sorry to complain but white text on black background might look nice but it is almost impossible to read!
Otherwise thank god you are doing what you are doing!
Regards
BIll

it may be necessary to require blog posters to state newton’s law of conservation of energy prior to posting.

Green energy: Solar’s Big Boom:
www.mercurynews.com/ci_7001523

Total required ampacity, 126 A
Available ampacity, 74 A
A 1,700 sq. ft. house in Modesto, CA
Electricity provided by Modesto Irrigation District - yes, it’s farm country.

The main breaker is 200 amp, but the total for all the branch circuits is 460 amps! Good thing we never have everything on at once. There is 240 volt circuits for range, dryer, and AC, and a 240 volt 30 amp circuit that isn’t connected to anything - I’ve checked, it’s off and everything runs.

I have the technical skills and space in the main panel to wire in a 240 volt 70 amp circuit for an EV charger, now all I need is a lot more money to buy a Tesla. Penny pinching time! Hey, maybe the whitestar sedan will be ready when I am…

the portable power unit that i have might be able to run your charger just need to know more abought it
i will start showing the unit this weekend and building them after that if all goes right i can step it up more to handle the charger

Dear Editor,

How many watts input to the charger does it take to charge the Tesla and how far will it currently go on this charge? Does the efficiency of the charging vary with the speed of the charge and the initial charge level of the batteries? Do you have any comments or views on the Firefly batteris that look to be very low cost and would probably be very cost effective although at some sacrafice? Thank you.

Martin,

Why not dedicate two panels to your charging system? 1 for AC power and another for DC power. The current NEC code has little to zilch language on the limitations of DC systems and a company like yours could help set the stage for the NEC verbage of how to integrate electric car charging into residential and commercial applications.

Although i wish to see your electrical system for the roadster I can make the assumption that the core of your power supply is DC. WHY LOSE POWER IN AC TO DC TRANSLATION, KEEP IT AT DC. Electric car charging should be handled in an DC method.

The main reason I’m writing is to advocate an International Design Competition geared at Architects and Engineers to design your company’s most perfect R + D facilities now and into the next “gears” of Tesla. Thank you for reading.

Kyle Schertzing
University of Michigan TCAUP 05″

—-

Editor’s Answer: Direct from Martin

We are with Nikola Tesla on this issue. The trouble with DC (as Tom Edison quickly discovered) is that it is impossible or at best horribly inefficient to change the voltage of a DC source without converting to AC along the way. Thus, if your solar panels are producing 250 volts at the moment, then you simply can’t charge a 400-volt battery. If your panels are producing 600 volts, then you will lose 33% of the energy dropping down to charge a 400 volt battery. The efficient way to switch DC from one voltage to another is with an inverter - an inverter converts the DC to AC, puts it through a transformer(or equivalent) to step the voltage up or down with surprisingly good efficiency, then rectifies the AC back to DC at the desired output voltage.

Inverters are getting pretty darned efficient. The inverter in a Roadster is around 90% efficient (While charging, this inverter rectifies the AC charging voltage. While driving, it converts the DC from the battery into AC for the motor - or the other way around for regen); the inverter on my solar panel array (which makes AC out of the DC from the solar panels) is maybe better than that. This system works over a very wide range of voltage from the panels and also over a wide range of voltage in the battery.

Counter-intuitively, passing through AC is about the most efficient way to charge a DC battery from a DC solar panel array.

Best, Martin

Charger Standards. Editor: Thanks for responding regarding V2G. It looks like PG&E is not yet talking about bidirectional, but allowing them to control chargers (I presume over the Internet?) will be helpful—and probably required—to avoid brownouts, especially in CA. I’m hoping bidirectional is on the roadmap.

But this raises another charger issue: standards. I assume the onboard 120v charger uses a standard 120v plug, but from the pictures I’ve seen, the 240v charger uses a special adapter. And interfacing with electric utilities like PG&E for sophisticated control of charging adds a significant new communications layer to something that should become a standard.

My interest in electric vehicles in general and Tesla specifically stems from my broader interest in the establishment of an overall electric economy (if I may be so bold, I’m putting together a blog for like-minded individuals: www.geopoliticsofenergy.dyndns.biz). During my research I was fortunate to find Tesla early on in its published life. In addition to becoming an important proof-point for the establishment of an electric economy, Tesla has taken the concept of electric cars to a very exciting place, whether we are able to clean up our energy act or not. But to have a market you must have more than one player, so I’m glad to see a few potential competitors making an appearance. Ironically, I believe for Tesla to reach their full potential as a business they need successful competitors that will need to share charging infrastructure.

Any work you can point to on the charger standards front?

Thanks, Harley Dave

# TEG2 wrote on October 3rd, 2007 at 1:08 pm
# During the “Living with Ed” show, GM was showing a rather surreal / bizarre commercial for the Volt:
# www.youtube.com/watch?v=R_J2Jx51XZs

[Announcer] And you can get up to 40 miles without burning a drop of gas.
[Children] Wow!

sigh.

Martin,

Here is what you do.
Design the charging circuit to work with the minimum available power permitted by the NEC, this is 180 VA for a general purpose wall outlet @120V. Everyone has a general purpose outlet in there garage!

1) Assume that the minimum available power at the outlet is 1.5 Amp/hour @120V as a minimum.
2) Depending how fast Tesla would allow the battery pack to fully recharged. Provide the custormer with the required amps needed at the outlet for this to happen. The customer will then decide if he needs to upgrade his circuit.

The minimum reserved VA (Volt Amp) for a general purpose outlet permitted by the NEC is 180 VA. @ 120V this gives you 1.5 Amp available at the outlet.

Required Amps: 290
Available Amps: 110

My 400A panel has a 200A breaker for the main circuits and a 200A breaker for a subpanel. But the subpanel is now limited to 60A because I wired my solar inverter / backup system into it. So, I may still have some electrical code trouble upsizing an unused 40A EV charging charging circuit to 90A on the main 200A breaker, but worse comes to worst I can have the two 30A 240V dryer circuits removed, since they aren’t being used.

The tougher challenge is finding additional South-facing area for another 2 kW of PV to offset 50 miles/day in Tesla driving. Most of my roof is either shaded or facing East/North, and I’ve already maxed out the vacant lot with an existing 5 KW array.

Jamie, you may be interested in this blog entry, www.teslamotors.com/blog4/?p=55.

I wonder if the technicians at Tesla Motors have looked into Nano Titanate batteries. From what I read they are far superior to lithium Ion and would be a huge advantage to the Tesla Roadster especially in public acceptance in terms of recharge time, safety and life expectancy.

Now that there is electrical survey which is directly useful for Tesla I suggest this for some future blog entry:

Survey: which practical sedan _looks_ coolest for you.

That is to aid Whitestar designers to create cool, but still practical exterior for a car (it isn’t too late, is it?).

My vote goes to Honda Civic type R 2007/2008 model. That is actually hatchback, but I’m not quite sure how “sedan” could be defined. Anyway, I like it.

Timo: Since the Tesla ESS is built up out of the same kind of cells as a laptop computer, my guess is it follows the exact same charge curve. If that’s true, it’s a fairly linear charge rate up until 85% or so, then it slows down.

If the Tesla ESS takes 3.5 hours for ~230 miles of highway range, you get a little over 1 mile per minute of charge, so maybe 2.5 hours to get 150 miles plus extra for safety. Note that you need 240volts/70amps to get the fastest charge rate, which could be a problem until Tesla-compatible charging stations are easier to find.

# Timo wrote on October 11th, 2007 at 12:57 pm
## Survey: which practical sedan _looks_ coolest for you.
## That is to aid Whitestar designers to create cool, but still practical exterior for a car (it isn’t too late, is it?).

Teslamotorsclub is back up! Check this out:
www.teslamotorsclub.com/showthread.php?t=312

# Ryan Lamansky / Kardax wrote on October 11th, 2007 at 3:18 pm

# Timo: Since the Tesla ESS is built up out of the same kind of cells as
# a laptop computer, my guess is it follows the exact same charge curve.
# If that’s true, it’s a fairly linear charge rate up until 85% or so, then it slows down.

Which means that charging from empty to 85% is faster than charging from 25% to full. How much faster is the question. Do you have some link somewhere where those battery charging curves can be found?

# Note that you need 240volts/70amps to get the fastest charge rate, which
# could be a problem until Tesla-compatible charging stations are easier to find.

Well, I live in Europe in Finland, so for me this is still just theoretical. In here we have 230V system and for three phase you get quite a bit more. That means that amps don’t need to be that high. Of course Telsa doesn’t have any chargers designed for European currents, so it still needs to designed before this is possible.

Anyway, I’m quessing that if you make it compatible to basic european three-phase connector I can get some gas-station to serve me just by phoning them. They would probably let me charge my Roadster/Whitestar just out of curiosity. I would of course pay that ~5 euros for that service

Martin, I sure wish I could put my statistics degree to work on your Excel Spreadsheet, but most of my generation doesn’t own a 2 car garage or even home for that matter… In fact, most of the human beings on planet Earth don’t own homes or can plug in… I sure wish there was a cheap electric car that could run on solar panels that were part of the body of the car or something… I’m worried that the projections from 800 million vehicles currently to 1.2 billion in the near term and 2.5 billion around 2030 play out only to increase demand for cars that don’t require homes and special Hyatt chargers… It would be great if your next car could serve mankind somehow… Maybe a universal plug compatible with any plug anywhere around the world…

If transportation is responsible for 1/3 of smog today and the fleet of cars and trucks triples tomorrow, how will mankind survive (assuming that the fleet expansion ratio is the same as it is in China right now = 99% cheap internal combustion engines)? I wish you luck in attacking the auto industry’s 60 million per year output and cheers for reducing smog.

Energy Storage Technology Advancement Act of 2007 (Introduced in House)

www.thomas.gov/cgi-bin/query/z?c110:H.R.3776:

As well as the TEG, there may be some opportunities for the Tesla 16kW public charging stations.

Required: 129
Available: 71
Location: Coral Gables, FL

I still like the idea of exclusive load sharing 50A, 240V device as a less expensive charger option to installing a dedicated 70A circuit or worse upgrading one’s panel too. Not a big deal for the $98K Roadster, but would be more viable for the $60K sedan.

Available ampacity 231A
Required ampacity 169A

I guessed on the high side for loads that I wasn’t certain about - 400A service.

“Honda Won’t Pursue Plug-in Hybrids” (WSJ article):
online.wsj.com/article/SB119313344275568239.html

hybrids are an ignorance-induced stepping stone to all-electric since every auto lobbyist from 1973 forward has stamped out any congressional murmur about serious research investment in auto-specific battery technology. apparently some automakers feel (only 30 years later!) that they no longer need to prolong the excrutiating time and energy wasted on this intermediary (and cumbersone) makeshift technology. it’s refreshing to see some environmental common sense from the auto industry, even if it’s blatently profit driven. too bad it’s so furiously intermittent. the forecasted time span between traditional ice and all-electric must now be short enough that honda et. al. realize they’re wasting their money designing/building bloated hybrid clunkers. with auto batteries conquered, next will be the big trucks (and quiet city streets, can you imagine!!), boats and ships, and somewhere in there, grid-independent solar homes.

with respect to tesla, at the very least the company/car will forever be the iconic symbol of the first true successful transitionary vehicle (we hope!), with the ev1 as the sorry, misguided, trampled whiff. with the threat of the big manufacturers coming on strong, tesla has very cleverly positioned itself with a unique opportunity to take hold in the soon-to-be burgeoning and radically morphed auto industry. but only with persistent brilliance and guile (read: flawless product delivery and massive marketing effort ) will tesla be able to join the rank of the good ‘ol boys as a major manufacturer. the alternative, which is much more likely and certainly more prestigious than an exhausting fight with the goliaths, is to earn a seat with the elite exotics, continuously pushing the envelope and offering the fruits of cutting-edge technology to the masses. when formula1 is all-electric, and tesla has a team (and rocket chair), that’s a day to celebrate as the ev’s true coming of age!

~ian

I know you folks have your hands full (to say it mildly), but I wanted to toss out the suggestion for a “Roadster Light” someday:

35kWH pack
One gear
90MPH top speed
170mile average range
2300lbs (2/3 ESS capacity and no transmission might get you there already)
$80,000

a company creating an electric car that ’s putting emphasis on environmental concerns and consumption/output would be producing an electric car at a price point (and production numbers) that is realistic for the many….not an exclusive niche vehicle

Can you please see about this fellow inventor and provide him with council.

www.teslatech.info/ttmagazine/v4n4/pantone.htm

Jay Leno puts 54kW PV on his garage…
www.popularmechanics.com/automotive/jay_leno_garage/4228638.html

# www.lwv7.co.uk/programme26_07.html

# Editor’s Answer: According to the schedule Lotus is presenting, so I expect they will be there
# We have presented in the past, but not this year.

Doh! I missed the entry for Lotus Engineering!

My reason for asking was really in respect of the Whitestar development, but I appreciate that at the moment, you are all a tad busy

are you going to show the car at the houston car show?

I am seriously considering purchasing one of your products and I am planning on doing a heavy up to my electrical service for another project. I am curious as to the amps needed for the Power Station needed to fuel the cars. As long as I am changing the service I might as well plan for the car too so I don’t have to do it twice. I can not find any info about the Power Station and its electrical requirements. Can you please post them or a link to the info for me…… Thanks

Kevin Harney just posted a inspiriting post. What are the requirements for Power Station for single car. Combined to Ricard Pardells post about solar panels how much it would cost to put up one of those. I know Kevin is talking about his own “power station” and not something that could be used as “service station”, but lets extend this a bit.

Here is the question: If we put up an solar powered service station for Teslas what would it need? How much would it cost?

First of all: One S4000 solar panel (www.sol3g.com/downloads/eng/Sol3g_S4000_en.pdf) is enough for servicing one Tesla if we assume that it gets serviced every third day for full charge. Then we need batteries for storing excess energy for days it doesn’t serve Tesla. What is _cheapest_ battery tech that can store 53kWh of power if you count maintenance and replacement (if needed) in it. It doesn’t need to be small like car ESS.

16000€ one time cost for solar panel. Then there is battery for storing. Then maybe site rent for putting that up. Someone must keep that running so there is some salary cost too. Could that ever pay itself back? Does it have to?

If, lets say five, Tesla owners put that up in somewhere between some place they would like to get every now and then, but can’t because range is too limited, expenses could be divided between owners. 16000€ is about 22400$ / 5 = 4480$ for solar panel. That is very tolerable. How much about batteries (flywheels, whatever)? What about site rent? Tesla owners club anyone? Tesla itself? How about mapping the “hot spots” in the roads where two potential charging places are too far away form each other, and use some of the gained money to build up Tesla service stations where owners need it?

I think the Tesla Roadster is BEAUTIFUL and the technology is great, remarkable performance! But, why not make a car for the masses, say a sedan thats just as beautiful with 1/2 the engine power, which should make it go twice as far and charge up in the same amount of time and put the price 1/2 as much, say $45-50k? I think that would be a hit!

# Kareem Watts wrote on November 18th, 2007 at 3:52 pm

## I think the Tesla Roadster is BEAUTIFUL and the technology is great,
## remarkable performance! But, why not make a car for the masses, say
## a sedan thats just as beautiful with 1/2 the engine power, which should
## make it go twice as far and charge up in the same amount of time and put
## the price 1/2 as much, say $45-50k? I think that would be a hit!

That is exactly what they are doing or, to be more precise, will be doing. see www.teslamotors.com/blog2/?p=8

This REALLY needs to be somewhere in forum FAQ with cat-size letters “READ THIS FIRST”.

Nothing wrong with your question Kareem, but this really has been asked about ten times now. Or more.

Editor: Is it possible to get another tab in blog-page that says “FAQ” and which just answers questions that raise here again and again and again?

I love what Tesla is doing in the auto industry. I wish there were a group of people just as committed to changing the way we build houses in this country.

Looks like you aren’t the only ones not able to attend the The 7th International Conference on Materials for Lean Weight Vehicles.

It’s been re-scheduled as a “Webinar”

www.lwv7.co.uk/

Martin,

Thank you for the Roadster. Thank you for the vision of entering the top end of the market and driving downward. And thank you, most of all, for being the guy who will be remembered as the man who changed the world.

Best wishes to you and your family,

Mark Tomlinson

Martin:
What happened??? Your name is no longer on the Company Team. I am sorry to see you go, I will always think of Tesla Motors as being your company.
I know you are self described as a start-up guy, and in the case of Tesla Motors you have done an amazing job. I wish you the best in what ever future endevours you get involved with. Here’s one that I would like to do, make conversion kits for tractor-trailer trucks. When this becomes a reality, all trucks will convert to be able to stay competitive with the lower energy costs of electricity vs diesel fuel. They will do it to save money, the world will benifit with lower pollution.

The TESLA Sports is the way forward if we stop attempting to light the night sky (and the universe beyond) if we use the energy created at night to charge our EVs. I once had a TR8 with its 0-60 in 6 secs and and a gas mileage of about 15 mpg around town.
The idea of 0-60 in 4 secs and an equivalent gas mileage of 135 mpg is stupendous. We need to get Utilities to understand that the cheap night time energy wasted lighting empty streets on city blocks is adding to CO2 emissions, global warming and climate change. If we ALL had EVs that we charged at night then no long tailpipe but very unhappy Big Oil (?) unless they invest in hybrid and EV. Just common sense for a sustainable future to me? Sadly Big Oil want the big bucks now - we pay later.

I see in the FUTURE is people and their ideas , and their country , and their children will build global new economies by and for the people with there own ideas with a word FUTURE has a meaning to all .Can help all , in meny ways im like tesla , have ideas want to hlep all people all countries , and I Am a head of my time .and president /founder/solepriortor of www.futurevisionaries.com

Hey guys. This may not be applicable to this discussion about the electrical service available, but I wanted to make Tesla motors aware of new supercharge ion batteries that are under development by Toshiba and will ready for use by March 2008. I hope this is useful, I really want to see alternative/hybrid/electric cars work and be affordable in the coming years for everyone! ecofuss.com/scib-recharges-in-5-minutes-has-a-lifespan-of-10-years/

Good Luck to all of you at Tesla!

Hello,
My name is Sam Birchenough, I am a senior at Skaneateles High School and I am very interested in electric powered vehicles. I am interested in the design and evolution of the electric vehicle. I am doing a 20 page policy paper and was hoping you could help me out with the thought process behind the electric vehicle. I was wondering if you would mind answering a few general questions about your design.

1. Would the technology used in your cars be able to be used in electric cars that would meet the needs of the average middle income American family?

2. What type and what quantity of batteries did you use to power your Tesla Roadster?

3. What is the drag coefficient of your Roadster design?

4. How long did you spend on the design for the Roadster before it entered production?

5. Do you find that having a large rear weight bias (assumed) affects the performance of the car in a negative way (specifically cornering balance)?

6. Does your car incorporate what would be the equivalent of a limited slip differential?

7. Is the steering power assisted, and if so, how is it powered?

8. What percentage of the vehicle cost covers the motor, speed control, and batteries?

9. Is the motor brushless?

10. How does the braking system work and is it comparable in precision and performance to that of a traditional disk braked vehicle?

11. Do you find that cooling for the electronics is something that is tough to address?

12. How does the integrated battery charging system work without decreasing efficiency?

13. How much does the car weigh and what does is the power to weight ratio?

14. Does the car use a direct drive, a traditional transmission, or a variable ratio transmission?

15. At what speed does the car perform most efficiently?

16. What made you decide to produce a sports car design?

17. What do you think is a realistic time prediction for most drivers to be driving all electric vehicles?

18. How many Tesla Roadsters have you sold, to date?

19. Does the car use the speed control or a voltage converter to distribute the power to the rest of the cars functions such as the radio?

20. If you could only have one would you own a Tesla Roadster or an Ariel Atom?

21. What made you chose this career path?

22. Do you own a Tesla Roadster?

23. What do you think the downfall of the EV1 program was?

Thank you for your cooperation and your feedback!

—-

Editor’s Answer: Sam - writing papers is all about research. Most of your questions are answered in these blogs and on the website. Take a moment to do a little reading I took a look at your website - very nice (apart from the soundtrack!). You didn’t ask, but Nigel Mansell is The Editor’s favorite F1 driver

# Sam Birchenough wrote on December 19th, 2007 at 2:22 pm
## …lots of questions…

Although editor was right to steer Sam towards further research, here are some comments off the top of my head:

## 1. Would the technology used in your cars be able to be used in electric cars that would meet the needs of the average middle income American family?

That is their plan. To get there someday. Battery costs are still a barrier.

## 2. What type and what quantity of batteries did you use to power your Tesla Roadster?

6831 (18650 size format) laptop Li-Ions. Particular brand/manufacturer is proprietary info.

## 3. What is the drag coefficient of your Roadster design?

approx .3 from what I recall

## 4. How long did you spend on the design for the Roadster before it entered production?

Production is only just now about to start. The company started in 2003 so it has been about 5 years.

## 5. Do you find that having a large rear weight bias (assumed) affects the performance of the car in a negative way (specifically cornering balance)?

Apparently not too much. Rear weight bias gives extra traction on the drive wheels. The car has a low polar moment of inertia and I have heard only compliments about the handling.

## 6. Does your car incorporate what would be the equivalent of a limited slip differential?

Electronic traction control can provide similar benefit.

## 7. Is the steering power assisted, and if so, how is it powered?

Manual steering!

## 8. What percentage of the vehicle cost covers the motor, speed control, and batteries?

Probably proprietary info. Wild guesses: motor: 5%, ESS: 5%, batteries: 20%, chassis: 30%
But they have a LOT of R&D costs to recoup, so that data isn’t too relevant yet.

## 9. Is the motor brushless?

It is an AC inductance motor. It doesn’t need brushes like some DC motors do.

## 10. How does the braking system work and is it comparable in precision and performance to that of a traditional disk braked vehicle?

It is a traditional high performance disk braking system and apparently works quite well. The eMotor does simulated engine braking (by putting power back into the batteries) on the rear wheels to help slow you down as appropriate.

## 11. Do you find that cooling for the electronics is something that is tough to address?

I think the eMotor, and PEM are both air cooled. The battery system (ESS) is water cooled. I think they probably had to do some real engineering work to get all of those cooling systems to function adequately but it was never mentioned (publicly) as a problem area.

## 12. How does the integrated battery charging system work without decreasing efficiency?

I think you would need to explain this question better.

## 13. How much does the car weigh and what does is the power to weight ratio?

approx 2700lbs. 248hp/2700lbs (~0.09hp/lb). The very strong low RPM torque and wide RPM range make it perform 0-60 much better than traditional vehicles with those specs.

## 14. Does the car use a direct drive, a traditional transmission, or a variable ratio transmission?

Two speed traditional transmission. (which is still undergoing durability related refinements)

## 15. At what speed does the car perform most efficiently?

Oof. I don’t remember. I would guess somewhere around 45MPH.

## 16. What made you decide to produce a sports car design?

I think the founders all like sports cars and wanted to have one for themselves.
What they wanted to buy didn’t exist so they had to build it themselves.
Like all entrepreneurs, they decided to turn their hobby/passion into a business.
I don’t think they did this because it is an easy way to make money.

## 17. What do you think is a realistic time prediction for most drivers to be driving all electric vehicles?

Not soon enough.

## 18. How many Tesla Roadsters have you sold, to date?

Last reported they had over 600 deposits down.

## 19. Does the car use the speed control or a voltage converter to distribute the power to the rest of the cars functions such as the radio?

There is no conventional 12v battery for accessories. All of the vehicle power comes from the ESS “traction pack”. I am not sure if they use a voltage converter, or just have a dedicated portion of the pack just for 12v accessory use.

## 20. If you could only have one would you own a Tesla Roadster or an Ariel Atom?

Apples and Oranges.

## 21. What made you chose this career path?

To whom are you directing this survey?

## 22. Do you own a Tesla Roadster?

Nobody does yet!

## 23. What do you think the downfall of the EV1 program was?

Go watch “Who Killed the Electric Car”. They made a whole movie about that question.

If you have more questions start here:
www.teslamotors.com/learn_more/faqs.php
and here:
en.wikipedia.org/wiki/Tesla_Roadster

A very impressive product. I eagerly await a production version (i.e., affordable for the middle class) of the technology. With a little luck, the USof A could become an exporter of oil? Please hurry!

I hate to seem rude, but this is really kindergarten type stuff regarding electrical requirements.

Three points:

1). The range demand factors (eg: use 8kw for a 12kw range) is I HOPE obvious. Its almost impossible to have all 4 burners on high, and the bake, and the broil elements on for any length of time unless you’re purposefully trying to trip the breaker. This does not apply to the TESLA, since (again, they don’t say, but we’re left to assume) the charging rate will be constant throughout the duration of the charge.

2). Utilities in general charge a demand charge (aka electric ‘fine’) for any customer using usually more than 10 kw at any give time, and could cancel (cheaper) residential rate allowability. Why? In residential areas utilities usually have a 25 kva (lets call it 25,000 watts to avoid the powerfactor discussion) transformer for 12 homes. If too many customers have too many huge loads, the transformer will blow its top, or, at the very least, shorten its life. So, If you’re charging at home, forget about a fast charge until there is a cheaper way to buffer electricity.

3). During the 1/30/08 town meeting, the discussion by TESLA personnel was about homes having 40 amps available for a ‘dryer’. The only 40 amp availabilty in homes in the USA is by STOVE,RANGE, OR WELDER outlets (and then only, by those that have 50 ampere circuits for the outlets, and not the many that are 40 or 35). Dryer outlets are limited to basically 24 amps (actually, 22 amps of 240 and 4 amps of 120 - but the previous statement isn’t too much of a simplification). The official statement by TESLAMOTORS was just plain wrong. Very embarrassing that they don’t know this. I’m still hoping for an official spec-sheet on the Tesla. But listening to this ‘town meeting’ was unbelievably discouraging. It sounded as if they don’t know enough about their own car to even come up with a firm spec-sheet. And, I could never plop down a $50k deposit on something that is still in the vapor-car area. Weren’t there 48 TUCKERS actually built also?

I guess I dont really see the point of the spreadsheet. How many ranges will tesla’s customers have? Two at the most I would think. Another thing I have not seen addressed anywhere is how about those customer’s whose maximum voltage available is 208 (brooklyn, queens, (& other densely populated cities), appartment dwellers, etc). If that is just something Tesla wants to ignore, the customers could get a buck/boost transformer to jack it back up to 240. But we still don’t have any hard info from tesla on how to adjust the charging rate, and what happens when the voltage to the car changes.

To Russ Sciville: 99.9% of homes (and yeah, that’s an accurate number) in the U.S. are not ‘110 volts’. Half the 110 volt loads are in a series circuit with the other half of the 110 volt loads. Its old, but not an ‘antiquated’ system. Shock hazzard is much, much less than in Europe with “mains to earth” voltage of 240 (here it is 120). Distribution losses from the serving utility are calculated at 240 volts, since that’s essentially the load presented to it by the typical house.

Martin: I’ll end on a bright note: It’s my guess, that if customers of yours judiciously chose their recharge time, they could run a 70 amp (230) charger on their 100 amp service in the middle of the night. But the minimum service for purchasers of a $100k car are going to have a house w/ 150 amp minimum service 98% of the time. So if they have 2 spare spaces for the breaker in their existing panel, its a go. As I mentioned a few posts up, only one Tesla allowed per neighborhood or else the power company’s transformer will blow. So, for the time-being, I doubt that any initial customers of your cars will need to change their electric service, though we electricians charge a bundle for running 70 amp dedicated circuits to detached garages. - Bill.

P.S. Final questions i have not seen answered anywhere.

1). You say inv eff = 90%. What is the charger efficiency, considering power in/out of the charger alone.
2). What is the battery (ESS) charge efficiency, considering the battery (LI-ION) (including steering diodes) alone?
3). What is the battery discharge efficiency (ESS) including all losses with the exception of the 90% eff inverter?
4). Are the charging rates variable, or are there 3 fixed rates, (I assume 1 - 115, and 2- 230 volt). I see ‘charging module’ , “charging station”, and ‘extension cord’ used interchangeably. I suspect that the ‘rectifier function’ is built into the inverter, and there is no charging station, merely cords with differing plugs, but again, We Need A Spec Sheet. Thanks.

I performed the study using your spreadsheet and I got :
177 A
23 A available

The house is 2300sqft with 200A service. Located in CG Arizona we are equipped with two heat pumps that need 55A. If I should get an electric vehicle I would probably need another service line or if possible a device that cuts off the charger just before the heat pumps kick on then goes back on when they cut off. Is that even possible at a reasonable cost? The whole electric car idea is exciting and I hope it goes big.

Regards, Tom

I just filled out your Excel spreadsheet and found that the Total Required for my home (as currently configured) comes to 197A and leaves me with 3A remaining. It looks like I’d have to upgrade to a much larger capacity service for my home, if I add any high consumption equipment.

This is not a surprise. This home was built in 1965 as an all-electric home. Of course, these figures don’t tell the whole story, since our power consumption (as calculated from our electric bill) doesn’t come close to the maximum available power from our service.

Our maximum power useage is in the winter in Eastern PA and in the summer, our usage drops to about 1/3 of that.

Our local power company (PPL [www.pplelectric.com]) recently installed remote-reading meters throughout their coverage area and promises to have “hour-by-hour” power consumption listings available to each of their customers on their web site by the end of 2008. I’ll be very interested to see what that looks like when it’s available.

With the winter months coming in thick and fast I have noticed the difference in how much my energy costs are compared to last year so I think it is definitely a good idea to search for a cheaper electricity supplier.