Beating mother nature’s charging limitations for winter

[selfbp]

I’ve seen it discussed that charging will warm the battery up to allow for better temperatures for winter charging. Also I’ve read that charging before you drive can help you preheat the pack.

But is it possible to keep the pack warm all the time by keeping the charge rate around 10A~ (depending) to provide slow and steady charging throughout the entire night? Thus resulting in a better quality of charge, maintenance of warmer temps in the pack, and providing a full charge by morning?

I wonder if this can be done, because just like the Regen charge rate staying capped at sub ~50w in cooler temps, will the pack get warm enough during that slow of a charge since it isn’t charging at the usual higher rate?

I usually deplete about 20-30% battery per weekday, and the weather so far is getting to the 20* area here in my case, so I’d say others in even colder locations would benefit from this as well.

 

[Rocky_H]

I think the experience is that 10A is so low that it doesn't generate very much heat and won't warm the battery very much.

 

[rhumbliner]

I think his point is that charging a cold battery causes the battery heater to kick in first and then once the battery has warmed sufficiently then the charging begins. I assume (and this is just a WAG) that if charging at 10A isn’t sufficient to keep the battery warm then the heater will intermittently kick in and re-warm the battery.

So it would seem reasonable to assume that his suggestion might actually keep the battery warm all night. Whether or not this is practical or even desirable is another topic for debate, but I might try this as an experiment some cold night. Lately it’s only been getting down to 10°F at night here so I’ll have to wait for a chilly night.

 

[arcus]

Looking at this thread, it seems the battery preconditioning cuts off when reaching a certain temperature:
Energy consumption for Preheating

 

[tnt1971]

Charging, by itself, does warm the battery a bit, but it is not that significant. The battery heater will only come on at really low temperatures (lower than 20 degrees F).

I normally charge between 6 and 8kWhs. Occasionally, when it is really cold (below 20 degrees F), there will be a delay in the starting of the charge and it will ramp up slowly. When it is just cold (20 to 50 degrees F), the charging will start right away but the regen restriction is still mostly there. Below freezing it never disappears on my 40 minute commute, even if I charge for more than an hour before leaving.