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Days in question ~50F. There's a lot of room for error. Like maybe the pack is still cold-soaked from the last time it was outside. Or maybe I didn't charge long enough. But main point it I haven't yet come close to overheating. I've charged for a long time before, like 60% to 100% and max battery power still said 50 minutes to enable at the end of it. So the pack was still cold.
edit - I don't think the heat comes from the battery, it comes from the chargers. If I indeed have a more efficient charger than older cars, well that explains it right there.
A battery trying to shed heat due to charging at 80A would be a bonus garage heater that I'd welcome.
Charging at 80A is never enough to kick in cooling where I live.
Typically, battery HEATING can kick in when I stick 80A into it in the morning, to bring battery up to temp to take the full dose.
I do notice under the car can remain wet longer, when by rights everything in there should freeze. So ya, it's making heat.
So either way, heating or cooling the battery, any waste heat in the process of charging is a bonus garage heater.
I should just roll down the windows and turn the remote app climate up to HIGH while I'm at it.
Electric resistive heat has a power factor of 1 and Watt for Watt is an efficient way to heat the garage.
Charging at 80A is never enough to kick in cooling where I live.
Typically, battery HEATING can kick in when I stick 80A into it in the morning, to bring battery up to temp to take the full dose.
I do notice under the car can remain wet longer, when by rights everything in there should freeze. So ya, it's making heat.
So either way, heating or cooling the battery, any waste heat in the process of charging is a bonus garage heater.
I should just roll down the windows and turn the remote app climate up to HIGH while I'm at it.
Electric resistive heat has a power factor of 1 and Watt for Watt is an efficient way to heat the garage.
Soolim
Member
Justicepool
Member
Ok, just to make sure. 
I just had a second charger installed in my Model S so that I could charge at 80 amps on my HPWC. I did notice the charging cord and handle from the HPWC to be warm when I unplugged the first time charging at 80 amps. I never noticed this before at 40 amps. So.....this is ok?
I just had a second charger installed in my Model S so that I could charge at 80 amps on my HPWC. I did notice the charging cord and handle from the HPWC to be warm when I unplugged the first time charging at 80 amps. I never noticed this before at 40 amps. So.....this is ok?
dhrivnak
Active Member
After owning a Tesla for more than 5 years now, where I can charge at 70 amps (I have the older Roadster) it is vary rare I charge at more than 40 amps. I do this for three reasons. The first is VERY rarely, maybe twice a year do I need to charge faster. The second is it is not kind to the power company. If everyone on a block were to charge at 80 amps, especially at the same time transformers would begin to blow and EV's could get a bad rap. The final reason is I strongly suspect the more one stresses anything the shorter it's life. At a race track one is lucky to go 200 miles on a tire but drive with care you can get 40,000 miles. If you run a motor at full load it will last just hours but let it idle at 20% power it can last dozens of years. If you overclock a CPU or memory they will more often fail.
Now the Model S is designed for 80 amps and one can charge at that rate. But I would be willing to make a big bet that the electronics will last longer at 40 amps than 80 amps.
Now the Model S is designed for 80 amps and one can charge at that rate. But I would be willing to make a big bet that the electronics will last longer at 40 amps than 80 amps.
Warm is OK, hot is not.Ok, just to make sure.
Ok, just to make sure.
Yes.
Too hot to touch == bad. Warm is ok.
I'm not sure about that, because at 40 amps you are utilizing one of the chargers at 100% of its capacity. Now if you up it to 42 amps, and have dual chargers, then you are using both charges at 21 amps and are running them at ~53% of capacity.
Interesting. I charge my car at 80A all the time, and the car has never gone into active cooling mode (running the AC compressor). It will almost always, at any charge rate, run the battery coolant pump to keep the module temperatures balanced, cool the chargers, and occasionally cut on a radiator fan to either bring them up or down towards ambient and to keep the charger cool. The chargers themselves are on the same cooling loop as the battery, and they need cooling at any temperature (on the bench, with 120V/5A charging the charger goes into thermal shutdown within about 30 minutes if I'm not actively circulating coolant through it). Most of the pack heating actually comes from waste heat from the charger. It uses the pack itself as a big heat sink. A full charge from near 0% to 90% at 80A barely raises the pack temp at all. Keep in mind that 240V/80A charging is less than 1/4C rate of charge after conversion losses. Seems like a lot, but it might as well be a trickle charge for these cells.
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