JeffN wrote: LeftieBiker wrote:
It's always nice to read a piece with no typos or mistakes. Good job. I do have one question:
When a dedicated 2 kW battery heater is available (as in the Canadian version), it is used primarily at sub-zero temperatures (0C or 32F) or when the driver enables an optional “Winter Mode”. The battery heater, if present, is located outside the battery pack and warms the liquid “coolant” just before it enters into the pack.
Battery warming really starts at 32F?
My understanding is that battery warming using the dedicated battery heater, if present, starts at 32F if “Winter Mode” is disabled.
Some amount of heat will be exchanged from the motor, motor inverter, and on-board charger when the battery heater is not being used and temperatures are cool but above around 32F.
I think you mean, and the article states "the battery heater is used primarily at sub-zero temperatures (0C or 32F) or when the driver enables an optional “Winter Mode”.
Which makes more sense to me
As an EV'er in a northern climate which can get as cold or colder than areas of Canada, I'm not too happy that the winter mode will not be available to people in the US, only Canada
at least for the '19 model year. I also dislike that without the winter mode, you'll be stuck with just a resistive heater and not the much more efficient(at least at moderate(teens F and above temp) heat pump heater)
which I feel is pretty short-sighted as it's in just those moderate temps(and not sub-zero F temps) that a heat pump heater shines.
Another interesting point from the article:
"The winter mode uses extra energy to warm the battery pack to allow for full regenerative braking and quicker fast DC charging. Colder pack temperatures force the battery management system to restrict the amount of power that can recharge the battery in order to avoid damaging the carbon graphite anode. This is an issue common to most lithium ion batteries. Cold temperatures are not much of an issue for power coming out of the battery except under rare and extreme conditions like down near -40 degrees."
Luckily we rarely get below 20F in Minneapolis, -30F is about as cold as it ever gets. Northern MN is different where it can get -40F several times per winter but few people live in those areas and because things are so spread out there, an EV probably wouldn't be as practical.
Another quote indicating "winter mode" is enabled to start battery heating.
"When temperatures are really cold, the dedicated battery heater kicks in (if present) even if “Winter Mode” isn’t enabled."
Oh and if I did my calculations correct, the weight of just the battery cells of the 64kWh would weigh ~525lbs, guessing closer to 600lbs or more with the case and coolant loop material(just an FYI).
I agree with Leftie, a nice and very informative article