[Ovmsdev] Cooldown

[Tom Saxton]

on 5/12/12 8:22 AM, David Morse wrote:

> I am curious though, does anyone have evidence that the cool down feature in
> beneficial?  If so, I wonder why this is something Tesla never implemented.

Tesla recommends that you plug in the car whenever you can and especially if
the battery is hot. This is problematic if your electricity is billed on
time-of-use, or you want to do your charging off-peak for some other reason.
So for days when you arrive home with a hot battery during the day and want
to be nice to the battery, but also want to limit your use of power during
peak demand hours, a cooldown feature is highly desirable.

I installed a Tesla Tatter last summer and used the cooldown feature a lot,
it's very nice.

It is an open question as to how beneficial it is to battery longevity.
Drawing lots of current from a hot battery is definitely bad for battery
health; that's been proven by several Roadster owners. It's less clear if
letting a battery pack sit hot while drawing little or no current is a
problem. To delay a $40,000 battery replacement, I'm happy to err on the
side of caution.

In August of 2009, I asked Tesla to implement a cooldown feature and was
told:

"The idea of allowing you to cool the pack while only pulling enough energy
from the wall to do so is something that we've talked about. Unfortunately,
although the idea is simple, there are some significant hurdles in
implementing."

That didn't stop Scott451 from doing it, with no help from Tesla. Now Scott
works for Tesla.

    Tom