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Battery Preconditioning Question

Posted: Sun Apr 21, 2019 10:27 am
by symonray
Hello. I am familiar with the requirements of setting a departure time at least three hours in advance and having the vehicle plugged into the charger in order for the battery to be preconditioned prior to departure. But, does the vehicle have to be actually charging during the entire three hour period or merely just plugged in for battery preconditioning to occur? I normally charge my vehicle up to about 75% every evening (which is many hours before battery preconditioning is supposed to start) and then schedule my charger to charge an additional 10% about 30 minutes before my departure time in the morning. So, although my vehicle is plugged in all night, it is only charging about 30 minutes of the 3 hour period. So, with this charging schedule, will my battery be preconditioned? Thanks.

Re: Battery Preconditioning Question

Posted: Sun Apr 21, 2019 7:48 pm
by jadnashuanh
The vehicle must be able to activate the EVSE when it wants, or battery preconditioning won't happen...IOW, it must not only be plugged in, whatever control you have on the EVSE must allow it to apply charging power to the car. That means, you would need to enable the EVSE to be on at least 3-hours prior to your departure time, and probably 3.5-hours would be better if it's cold out. The car won't need the full amount of time when the weather warms up.

I've seen mine pulling over 20A when it's cold out while also preconditioning the cabin. The battery heater is 1000W, or just over 4A of that, so over 16A peak to condition the cabin. That's probably an extreme example.

The car can turn on cabin conditioning regardless of the EVSE being attached, but not the battery conditioning.

Re: Battery Preconditioning Question

Posted: Mon Apr 22, 2019 7:56 am
by symonray
That is very helpful. Thank you.