Forums

Join The Community
RegisterLogin

Battery Charge Loss: Overnight

Does anyone else notice that their Model S loses charge over night? I went to Tesla Menlo Park yesterday and told them this, but hey said that the charge loss would replenish itself once I started driving. They explained that this was due to the cold temperature at night, which caused a misreading in the morning. My takeaway from the conversation was that the battery under cold temperatures acts similar to that of a car driving up or down a hill: the "gas tank" misreads the level of fuel in the tank.

So I took my car home last, checked the mileage, went to breakfast this morning, and not only did the car register 30% less charge but it did not replenish. It also lost 2 miles of charge for a 1 mile trip. I drove normally. I checked my phone and it had been logged in to when I checked the mileage last night before I went to sleep: 61 miles
It changed to 38. It was at 40 before I drove to breakfast.

I believe it lost 30% the previous night. 102 went to 70 something.

I just picked up my car from the factory on Thursday 2-14-13, so I'm a little new to this. Does anyone else have this problem?

Blake

98% of the time I plug my car in at night. On the few occasions I left it unplugged overnight, it lost about 10 miles of range in 30 F temps. I'm in Ohio. I have noticed on really cold days 12 F while parked at work I would get home with 150ish miles of range out of the 230 I had in the morning. That is a 42 mile round trip. 50% highway. So some was warming the battery after i started driving and some was loss while sitting. The android app wasn't released until after our cold snap so I wasn't able to pre warm the car. In the really cold temps my wh/mi were around 550 and in 45 F or greater I use about 300 to 350 wh/mi... depending on how heavy my foot is on the highway :) Usually drive 80. I have found that 45 F seems to be the tipping point for using more energy to warm the battery... at least that is when I notice the wh/mi going up.

Going to bed tonight with 250 miles range - will update status in morning - expect low 40s over night - first time over night

250 miles rated range @ 10 pm
241 miles rated range @ 7:33 am
Low temp over night 33 F...

That's my one data point

All,

It looks like a lot of the confusion here is being created by using the "Rated Miles" number as the amount of energy left in the battery. This number is a computer generated number based on a number of things, mainly temperatures. We should instead be looking at the battery level. This is shown both on the dash, the app, and (most easy to read) the big 17" screen. If you watch that, you will see that during these cold soaks that cause the "Rated Range" to drop, the battery percentage has not moved my any more than expected due to the lack of sleep mode.

For example if you go to Nickjhowe great graphic, you can see that the battery percentages for each day are about: 74%, 72%, 68%, 65%, 62%, 59%, which fits with the range displayed also as the car was kept at about the same temperature the whole time.

Peter

@Peter7

Where do you see battery percentage on the dash, app, and touch screen? I must be missing it.

They unfortunately don't display the number on the screen, though you can snag it from the API if you mess with that stuff. But you can see the 10% marks on the battery displays, the rest is rough estimation. It's not perfect, but it does work.

Peter

For mine, the drop is closer to 1 mile per hour. I left mine in the garage at around 40 degrees for two nights and a day and the drop was over 30 miles, from 157 to 124.

Even now, when I left it outside where the temperature is over 40 degrees, the drop is 1 mile per hour, from 55 to 51 in 4 hours.

I can't charge it every night as the apartment complex isn't letting me use any power outlets. And I desperately need the sleep mode. Is there a way to rollback the software version, from 4.2 to 4.1, for just the sleep mode?

~ Prash.

@Peter -- I don't see 10% marks on the app. They might be on the displays; next time I get in the car I'll put my glasses on to look. I never noticed them before.

@Peter;
OT, did you see the "Buddy Box" that was referred to elsewhere?
http://elecordset.com/moreinfo.aspx?pid=QSBB-50&cs=/products/rv-accessor...
How does that relate to you MI-EVSE?

typo: to your MI-EVSE

While this is not mine, I agree and think it bears repeating:

"I'm an engineer and am able to estimate range/conditions/etc (and enjoy it!), but to be really mainstream, I think Tesla can/should do more to help drivers manage their driving - they have not been really clear/open about parking- and temperature-related losses and the on-board tools and the app don't really help you estimate where you really stand. For example, they could integrate Nav, Weather and Energy apps and really give you a trip planner that takes a lot more into account. Right now, for example, I have to consider speed, route (climbs) and real-world consumption to plan a trip. For example, while you might have enough total energy to get home based on average consumption, if there is a big climb shortly before you get there you can still run out before the top! As more non-tech and non-early-adopter types buy, it will be too easy for them to mis-estimate and get stuck with the current tools."

There is one thing I am not clear about. I hear folks are charging in the cold and it seems as if they are not stopping at 80% but are allowing the battery to be charged all the way to 100%. I believe I saw recommendations to charge only to 80% since 100% will diminish the battery's capacity over the 8 year length of the battery pack. Has anyone else received this instruction?

It seems to make a difference if you start driving right away. Sitting at 100% is the real problem.

@Damian,if I understood it right, they don't really charge up to 100% they put it on Range mode but don't allow it to lead fast, that way the battery pack will be heated when they leave shortly afterwards.

This is just a way to force the car to pre heat the pack. I don't know if that's still necessary with the app.

Hey BrianH,

Unfortunately it looks like the "Buddy Box" won't help. It still draws from a single 14-50, which is limited to 50A (40A continuous). My MI-EVSE needs two 50A supplies to merge to supply the 80A to the car.

Peter

My car was at service last week. They charged to max range and let it sit in the lot.

When I asked about it, they said if you do max range once or twice a week it's fine.

I am not so sure though.

Peter,

Is your MI-EVSE being sold?

Jay

I just started driving my Model S for the past 1 week. I travel everyweened from Yuma, AZ to San Diego, CA which is 185 miles. Yesterday was the first I drove this on Tesla. When I left Yuma I had 270 miles(standard mode charge) traveled at 67miles/hr(cruise cotnrol) when I reached San Deigo, was left with 28miles. Interior temp was 73 F.
I charged it in San Diego to 300 miles Max charge and parked in garage and within 8hours it has discharged to 265miles.
lost 35 miles in just under 8 hours.

@Damian: good eye on that engineering take. The basic problem is equating battery charge energy to "miles of range" when there are other demands on the energy, notably for environmental control, computer connectivity, hill climbing and the rest. My suggestion to Tesla:

* Allow us to put the main speedo display in energy units (as the switch advertises but doesn't deliver)

* Give us projected range (from the energy app) on the main speedo display of the energy app.

* Once that is done, follow the ideas below for integrating weather, Nav speed, topography, lodging and charger placements, with the energy app into an onboard trip planner like PlugShare, but better.

"I'm an engineer and am able to estimate range/conditions/etc (and enjoy it!), but to be really mainstream, I think Tesla can/should do more to help drivers manage their driving - they have not been really clear/open about parking- and temperature-related losses and the on-board tools and the app don't really help you estimate where you really stand. For example, they could integrate Nav, Weather and Energy apps and really give you a trip planner that takes a lot more into account. Right now, for example, I have to consider speed, route (climbs) and real-world consumption to plan a trip. For example, while you might have enough total energy to get home based on average consumption, if there is a big climb shortly before you get there you can still run out before the top! As more non-tech and non-early-adopter types buy, it will be too easy for them to mis-estimate and get stuck with the current tools."

+1 @ThosEM and @Damian


X Deutschland Site Besuchen