GetOffYourGas
Posts: 902
Joined: Tue Oct 20, 2015 5:25 pm
Location: Syracuse, NY

Re: Battery Climate Control?

Tue Jan 09, 2018 12:45 pm

IMAdolt wrote:I was under the impression the TMS will kick in weather or not it's plugged in running or not running till about 30% SoC? Seems silly to allow for battery damage in extreme weather to save a few watts of power for driving.


It will, and I have seen it do just that (and reported in the energy use screen). The temperature threshold for the TMS is lower when the car is off and unplugged, but it will still turn on to prevent damage.
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV (traded for Bolt)
2015 C-Max Energi (302A package)
2017 Bolt Premier

gpsman
Posts: 389
Joined: Thu Oct 20, 2016 9:10 pm

Re: Battery Climate Control?

Thu Jan 11, 2018 8:35 pm

Do the batteries really get damaged at any low temperature, or just become unusable?

These are “dry” cells. Not sure what, if anything can freeze.

GetOffYourGas
Posts: 902
Joined: Tue Oct 20, 2015 5:25 pm
Location: Syracuse, NY

Re: Battery Climate Control?

Thu Jan 11, 2018 9:11 pm

gpsman wrote:Do the batteries really get damaged at any low temperature, or just become unusable?

These are “dry” cells. Not sure what, if anything can freeze.


Our batteries have a liquid electrolyte, which can absolutely freeze. Lithium batteries without a liquid electrolyte are referred to as "solid-state" batteries. They are underdevelopment, but not yet employed by any EV on the road.
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV (traded for Bolt)
2015 C-Max Energi (302A package)
2017 Bolt Premier

gpsman
Posts: 389
Joined: Thu Oct 20, 2016 9:10 pm

Re: Battery Climate Control?

Fri Jan 12, 2018 3:51 pm

OK... Cold REALLY affects DCFC.

I’m only in San Francisco cold. So overnight cold soaks in the 40’s.

When I DCFC the charge rate follows pretty much a bell shaped curve. Slow to start, fast in the middle, slow at the end. But on a warm day with warm battery, I start with maximum charge rate.

Today, the car cold soaked all night at 48’F or 49’F.
I drove it ~30 minutes on the freeway, which warmed up the cabin, and you would think, the use, would warm up the battery.

It’s now 52’F outside. I’m thinking my HV battery pack is at least this warm, probably warmer from the 30 minute drive.

On a 50kw DCFC just now (which delivers 46 kw to the car on a warm day), the car is only taking 32 kw.

DCFC rate is reduced by 30% with temperatures in the 50’s. Which turned out to be 15 kWh hours, or 25% charge in 30 minutes on the fastest DCFC available. (16% to 41% in my case)

As the battery warmed up, the charge rate gradually ramped up.

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