Here's what happens when you don't use your Chevy Volt gas engine "enough"

[Daox]

Really, they don't even have a fan to air cool the batteries?!?

[MetroMPG]

My understanding is the Leaf pack draws cabin air through the pack with a fan.

EDIT: finding multiple references to the pack fan, but I'm not having much luck finding good info about whether it pulls cabin air or outside air. (If it's cabin air, it could use A/C or cabin heat as needed, at least when the car is in use or on the charger.)

[Daox]

Yeah, that is what the Prius does as well. I wouldn't really call that passively cooled though.

[rmay635703]

Originally Posted by 3-Wheeler

I can 100% agree with that!

With all the heat we've had this summer in Wisconsin, my range has dropped probably close to 40%, maybe more.

EDIT: My hunch is cells degrading.

Jim.

With all the heat we have had my Fathers Miles ZX40 has had its range surge to about 62 miles from 40miles.

[gone-ot]

...found this Govt battery analysis showing that 100% charge at high temperatures reduces battery life:

[Voltdriver]

I don't really think there is a good case that can be made NOT to actively cool the battery. From what I have read, and it could be complete crap, Nissan couldnt get the battery size they needed, and get a 3 person bench seat, with an actively cooled battery. It added too much bulk. As a result, they had to go to a passive cooling system to remove battery bulk and reduce the cost of the car. Nissan claims that it (active cooling) isnt needed, but that is CLEARLY not the case as being seen from the hot climate Leafs.

GM went SUPER CAUTIOUS with their design. By not allowing the user access to the total energy of the battery, any degredation is hidden from the user for several years. By adding in a thermal management system, they are reducing the damage done to the battery by heat.

According to GM, they batteries are actually degrading at a slower rate than they had anticipated (10-30% at 100k miles). It is the reason they REDUCED the cell reserve on the 2013 models. When they reduced the reserve, changed the battery chemistry and added an additional .5 kWh to the size of the battery, it resulted in 3 extra miles of range.

I think GM was genius on this approach.

[NeilBlanchard]

I'm fairly sure there is no active cooling in the Leaf battery pack. I asked that question directly of Mark Perry, and when I've seen the display pack, there is no fan that I have seen. I have never heard a fan running while the Leaf pack is charging; like there is on my brother's i MiEV, for example.

The Wikipedia entry on the Leaf battery does not mention anything about cooling.

Here it specifically discusses the fact that it has no cooling system.

They do say you need to avoid having the car in 120F+ heat for more than 24 hours. And maybe they will need a revision for hot climates?

[Voltdriver]

New Blog entry: Examing the EPA sticker and their assumptions on a user's savings driving this car. Warning: Lots of basic math

My Chevy Volt: EPA Sticker of the 2013 Chevy Volt: Savings Examined

[cfg83]

Voltdriver -

It seems like you could have a 3D plot that shows the "sweet spots" for different kinds of Volt owners. Because there are so many parameters I would try to turn them into ratios :

X = A MPG/ B MPGe = A miles driven at MPG / B miles driven at MPGe
Y = ??
Z = ??

Do you know what I mean?

CarloSW2

[Voltdriver]

Yup. Just am not going to commit the time to making one You can, and I'd be glad to post it