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The effects of outside temperature on efficiency in one graph

Two days ago, it was 65 degrees. Yesterday, it peaked at 30. My power graph shows the dramatic shift in power consumption that comes from the MS having to heat up the battery.

The left 15 miles are in 65 'F weather and the right 15 miles are in 25-30 'F weather. Both dry and both driven in the same general pattern. Looks to my eye like about a 150 Wh/mi difference.

Interesting, eh?

Glad I live in Miami a cold day in winter is 65 degrees F

Yup, the defroster, AC to head the cabin, and the seat warmers all need to take power from somewhere.

I stopped paying attention to how much energy the MS is using since I never use enough juice to go below 50 miles range for any given day.

It's a bummer there aren't any gauges in measuring how big my grin is after going on each joy ride!!!

cfOH,

I have noticed the same here in NJ. Did you have the cabin heat or seat heaters on in the last 15 miles or is that increase due exclusively to the battery warming?

Jonathan

Nice picture...thanks.

I need a garage.

I have noticed the same as temperatures have fallen. This additional energy consumption is party due to denser air. Cold = more dense air. Thus more drag.

I've actually had a totally different experience. In my drives from NYC to upstate NY recently (about 140 miles), in 35-40F degree weather, I've only noticed a small difference in range compared to my drives during the summer at warm temps. It's hard to quantify because of various variables, but I'd guess the upper limit is about a 10% knock on the range?

Maybe it's because you're commuting, and the warming of the battery takes a lot of power? (Which I guess is what you're saying. Just wanted to make the point that I haven't noticed much at all during my longer trip, and that's when you'd normally be very concerned about range.)

Now we'll see what it looks like when it's 0F degrees.

Not an owner yet - but seriously considering following test drive. Live in Denver area. Any issues noted by other cold weather owners if the MS is parked outside in near 0 or subzero temps? I would be parking the car outside while I'm at work and also when skiing. Is starting/driving the car in subzero temps an issue (other than the increased power consumption)?

It's only recently started getting colder here in New York. Starting should not be an issue, but you will not have full power or full regenerative braking until the battery warms up. I've only driven with the "Performance will improve when battery warms up" notification once, and it was fine for regular driving in the suburbs.

Isn't this problem going to be solved in the 5.6 update? - i.e., power from plug to maintain battery temperature - I can see where this would be very necessary if parked outdoors - if the initial part of the drive starts with a 30 degree battery use will be affected - IMHO

Negatives:
o Loss of some to all regen depending on temp.
o Battery heaters run to get battery warm. This increases battery life but causes reduced range.
o Cabin heater reduces range. Some owners only use seat heaters to minimize range loss. I use both, which is very un-Tesla like. But it keeps me very toasty.
o Last year some owners reported larger overnight range loss then in warm weather. Search http://www.volkerize.com/ for more information. Also vampire loss is less with newer software revs, so what you would experience should be less then last years reports.

First 3 items are greatly reduced after everything warms up. So on a long trip you don't loose all that much range. Lots of short trips yields a graph displayed above.

Positives:
o I find MS drives better then average in the snow (or at least when compared to the other cars I have owned).
o Passenger cabin warms up quickly. Since this is not dependent on the ICE warming first.
o Can preheat car via phone app.

Never a problem starting in the cold (at least down to 0F).

I second pretty much everything dtesla said. On long trips the impact is not that big, it is on short bursty commutes where you see a big hit (takes about 15 minutes to warm up). Also, what amazes my wife and I is how fast the car warms up. The car can be 5C in the morning. With the Tesla app we remotely have the car up to 20C in just minutes. It warms up MUCH faster than an ICE ever would, big bonus for us Chicago folks.

@cfOH - Have you set the car to "range mode". I noticed that setting makes a big difference in energy used in cold weather.

@dtesla: Good post...very accurate.

@TeslaOR: I have only used range mode once, this past summer, and I found the car didn't stay cool enough in August heat. I've not yet tried it in the cold weather.

ha, i took a pic yesterday of the exact same thing. looks very similar. for the first 5k miles (june to now) average has been 300 kw/mi... first cold day and average is ~330ish.

based on that I guess kw/mi should increase 10%-20% over the winter months.

@craig.weber - it doesn't get that cold where I live, but last winter I took it Chattanooga, TN where it was below freezing the whole time. I charged at the hotel the night I got there, and again 4 nights later before we left. I left it unplugged the rest of the time, and had no issues, and the heater really works fast compared to an ICE - it was melting the ice on the windshield in under a minute compared to maybe 5, and the cabin was warm in just a few minutes.

The Model S is also the #1 selling car (not just EV, but overall) in Norway, and they know something about cold weather.

5 mile commute vs 140: 50% vs 5% hit! It's all up front.

robgoodin;
Wimp! >;p

You guys are freezing and we're setting record temps: mid 90's all over SoCal today

I know this has been discussed elsewhere but just to refresh my memory... To avoid the battery warmup period issue, can you, what, either tell it to charge a little more right before you use it, ie while still plugged in? Or start the cabin heater while it's still plugged in?

Yep, just use the app to turn on the heater (climate control) 5-10 minutes before you expect to leave.

I've found that using the app to turn on the heater doesn't warm up the battery much. I had the heat on for 15 minutes and still had very limited regen when I first started driving. It took about 10-15 minutes of driving for the battery to warm up. This occurred after the car was parked outdoors, not plugged in, and it was about 32F.

It was cold in NJ yesterday. I turned the temp on @ 72 F 40 minutes before leaving work (car unplugged on the parking lot). It didn't appear to have helped with warming up the battery - got that yellow dotted line still.

This morning was cold too. Plugged it in for half hour charging and heating @ 77 F. To my great dismay - got that yellow dotted line still but to much lesser degree. So it appears that charging helps but not that fast.

I got tire/tyer warning (pressure too low) when leaving work two days in a row - have to say the warning itself is cute if not for the content. It went away after 1-2 miles of driving. Broke out the Tesla air pump last night - worked like a charm!

I was quite upset initially with the huge increase of energy consumption per mile when the temp dropped (daily commute only 17 miles each way). It was then mitigated by gliding down the hills, which is fun and energy saving. Now it's sub-30 in the morning, I just have to get used to the increase, for sitting in the toasty chamber is one of life's great pleasures for me.

Why would Tesla not be able to use shore power to totally warm up the pack? Or could it be that they're warming the cabin first and then the pack? Any ideas?

Hi!
I'm living in Norway, a country known to have a bit colder weather than what you are used to.
However, I do not understand your graph (and hope it can be explained by some extra high power consumption or way of driving) as we can have down to -20 °F where I'm living.
Today I drove from Oslo to my office, a distance of 65 miles and at an average speed of 63 m/h.
When I started, the estimated driving distance was 218 miles and whan I arrived at the office, it was at 150 miles which means 4,62% more power used than purely the distance (68 miles versus 65 miles).
My average is between 198 to 225 and for the first 2 800 miles (I just got it) I have an average of 218 Wh/km which means around 350 Wh/mile.
I'll keep you posted about my experience when our cold weather kiks in. :-)

I started another thread on this very topic - why won't the Tesla, after charging, just use shore power to keep the battery warm? I see no reason that you're plugged in, but charged, and you wake up in the morning to a car that needs to use battery power to warm the battery (or to set the cabin heat to come on remotely).

I may not know when I will be leaving, so if the electricity is available and it's cold, why won't the car use it to keep the battery at optimum temp?

I noticed battery warming significantly increases energy consumption while it is happening but stops after the battery is warm. While mine was warming in 28 degree weather I was going through 390 wh/mile for about 4 miles then it calmed down to near normal. You have some serious power spikes there, do the 4s 0-60 on every accel?

I am going long distance from Buffalo to Hamilton NY in a few weeks and will document that drive. I did this in warm weather averaging 323wh/mile on the thruway at 65mph and about 280 wh/mile on side roads at about 40-55mph. Both without seat heat, but defrost was on low (it was raining quite briskly at one point.

A nice option for the app would be a departure-time setting that would prewarm battery and cabin on shore power to be ready at that point.

@RonaldA

I already did just that. See thread Coasting technique long distance - RESULTS or words to that effect.

Robert

@Brian H: Yes, the app really could, and should, become a fully-realized control center for the MS.


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