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Did you know the 3 heats the battery (actively) constantly while DC charging at any speed or temp?

SageBrush

REJECT Fascism
May 7, 2015
14,121
19,550
New Mexico
but I understand your point

Nice.

To expand on this point, I take cold pack charging seriously seriously enough that in the winter I forgo the advantages of charging in the AM (better regen, perhaps better cabin comfort, less time at a higher SoC) and choose to charge right when I return from driving so that the pack is at its warmest.

The trade-off gains me 4 benefits:
1. Less regen -> more friction brake use. That does not sound like much of an advantage, but I don't want my rotors to rust
2. Less Li-plating, which is the underlying issue with charging a cold pack.
3. I can set my charge limit lower overall since the car reaches that limit (or near it) before the next car use.
4. The car gets to charge at home off our PV

(4) is a peculiarity of being retired, so the EV is usually able to charge when the PV is productive
 

Dave EV

Active Member
Jun 23, 2009
2,458
3,194
Earth
You guys do realize this thread is about unnecessary heating of the pack, primarly during 3rd party DC fast charging, right? @Jeremy3292 never said that ALL pack heating is stupid at ALL temperatures, sheesh!
Well, it also happens on urban Superchargers and on V2 Superchargers, especially if you are sharing a stall. So optimizing the amount of heating going on to what is actually needed to prevent lithium plating and maximize overall charging speed is important in a number of cases.
 
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Bjorn has tested this update and how it impacts charging at a 50kW charger:


And it seems to work as I would expect. With a reasonably warm battery, ~23*C/73*F, it charges at 43kW and does not heat the battery while charging. (It did still heat the battery when the battery was colder; ~13*C/56*F.)

It switches from heating to not heating somewhere between 56* and 73*, I wonder if someone will take the time to find the exact cut-point for that.
That is not my experience, that depends on the exterior temperature. When it was warmer, battery heating started about 48% SOC, but if exterior temperature is about 8C (46.4F) then warming up can start as soon as 40% SOC.


It is interesting that this that not seem to depend on the battery temperature, when I charge is at the end of my way home and the battery is always warm (about 26C (78.8F) if I recall correctly).

This is very inconvenient. The charger I use gives only 38 kW and I end up having only 30 kW for quite a while.

I also don't like to have the battery hot for a long time, so I stop charging before I would like to. I would be nice to know what is the sweet point in this process.

To what temperature would you let your battery go on a *daily* basis? I use to end charging when the battery is about 42C (107.6F), which these days correspond to about 60% SOC, but I wonder if this is too much stress for the battery or, on the contrary, I could even go hotter... I'd love to reach 70% SOC!
 
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FYI,
SMT series/parallel = 0 is Series on diag screen, and 100% is Parallel from my observation of both.

Battery heating observations, 37F outside, car sat for 12hrs.
Range mode and Car off or on:
View attachment 880598

Range Off, car off:
View attachment 880599

Range off, car On:
View attachment 880600
This one seems dynamic to me...

Also, my battery heater never turned on but i didn't drive with Range Off, just flipped it for testing.
While driving with Range On, it stayed in Parallel for about 10min (battery didn't heat at all) then went into Series n slowly started to heat the battery.
This is from a thread discussing the Model S, so they might not represent 3 / Y.
Passive Cooling Target means below 40c(104f), the radiator is bypassed, and all motor heat warms up the battery pack (yes, even in hot summertime). At 52c(125f), the A/C engages to cool the pack. You will get a little more range out of your battery the hotter it is, but Tesla will not allow the battery to exceed thermal limits.

Also, the hotter the pack is, the more it "resists" going even hotter, because the pack is a huge thermal heatsink.
Supercharging above 60% in 30c(86f) degrees outside temp seems to stop raising pack temp above 43c(109f). You are definitely safe to keep charging.
 
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