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Is charging affected in cold weather

I'm getting ready to drive about 200 miles one way. There is a 30 amp charger in the parking garage at the hotel I'm staying at. The temperature will get down to about 15 degrees F overnight. The parking garage is open so it is exposed to the weather. I wanted to charge to 90% and then top off with a range charge the next morning so I can make it home. Does anyone know if I start charging on a cold 15 degree battery will that take any longer to charge. I have a schedule to keep so I can't have an unusually long unexpected charge time. I have the 85kw battery of course.

I haven't noticed any effect. If the battery is cold it might have to warm it up first but that should only take ten minutes. Sounds like you will be arriving and plugging in so the battery will already be warm and ready to charge.

It will absolutely affect charging time. I've had my MS since last December and charging in 15-20 degree weather typically results in a 6 mile/hour recharging rate for me as opposed to 12-15 mile/hour recharge at warmer temps (this is with a 30 amp outlet as well). You could look at the dashboard while you are charging and see what rate you get in the cold.

@Ddowns

200 miles one way straight through would be enough to give me serious range anxiety in really cold weather. I wouldn't be inclined to try it. I would look for a good charging stop for lunchtime. Your charging will be slower on the lower rate outlets because a good amount of that energy will go into maintaining the battery temperature.

Do you have lots of experience with your car and the terrain that you will be travelling through?

BTW... depending on the outlet you might have to set the car for a range charge the night before. It takes a long time to top off a range charge.

Charging starts really fast but as you top off it slows to a trickle. Imagine that you are pouring water into a glass. You can blast the water from the tap at first but as you top off the glass you have to slow down. At the very end it is drip by drip.

@Captain_Zap

I have made this trip in the summer no problem. There is a charger at about the 150 - 160 mile mark if I think I'm going to have a problem. I just haven't done this in cold weather. I will only go about 20 miles in the early morning and then the rest of the trip in the afternoon when it will be about 30 degrees. The reason I ask about slow charging is that I made another trip and charged the car over night when it was cold. It got done charging in the middle of the night to 90 %. I turned the charger on the next morning for about 5 minutes and it only charged at about 5/miles per hour. I didn't know if this would improve or not. When I made his trip this summer I had about 60 miles of range left when I got there, on the way back it poured rain the whole way back and I had about 30 miles left. I will keep an eye on it and top off on the way back if I have to. But once I pass the last charger I have to go at least 150 miles which I don't think will be a problem. I just didn't want to have to charge and wait around for a couple of hours unless I have to.

You gain about 1% range for each 1 mph you slow down. 10 mph = 10%. Is that enough? It will cost an extra ½ hr driving, vs 2 hrs charging.

Temps that cold can make a big difference. I wish I realled just how many extra Wh/mi it took for a trip I took last January.
As long as you have a back up plan for a boost, all is good.

When the car is at 90% charge and you try to go to 100% it can take a couple hours with a 30-40 Amp charger. They slow down the charge at the very end for battery health no matter what the temperature. The lower the state of charge, the faster it charges. You get just a trickle towards the end when topping off.
The same thing happens when filling a gas tank.

I am waiting for my high power wall connector to be installed. In the mean time I am charging at 115V with occasional top-up charges using my dryer outlet - a bit of a pain so I don't use it all the time. The temperature has dropped to -20C (-4F) and I now find that I can't charge at 115V. I assume that it is because of the temperature of the car but there is no explanation from the charging display.

@BrianH - it is non-linear, as drag is proportional to the square of the velocity. I can get about 200mi at 80mph, 220 at 72mph, and 260 at 65mph, (all with moderate HVAC needs and elevation change) for example.

For the original question, if it is *really* cold, some energy is used to keep the batteries warm, so that effectively means you are charging slower. I haven't seen it anywhere near as much as @CarlE states, but it does reduce it somewhat.

As others have pointed out, the charge rate does slow near completely full, but unless you are charging at faster than 40A you won't see it slow down too much before the last 2% or so. What I have done is charge it to about 95% (halfway into the trip section), and then when I wake up switch it to max-range from the mobile app. By the time I am ready to go, it is fully charged and the battery is still warm, and it didn't sit completely charged overnight.

@KR1 - you only get about 1440W out of the 120V outlet, which can't keep up with any HVAC use at all -- if it is having to use it to heat the battery, then that is why you aren't actually getting charge into the battery.

Any concerns… check out this amazing video Tesla just did:
http://www.youtube.com/watch?v=TelUR5Bg9zE

good news is that the battery will be warm when you arrive. if you time it right the battery will be warm when you leave too, since charging warms the battery.


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