Weatherman wrote:jstack6 wrote:Imagine how much extra energy is used for the battery cooling. I have both a 2013 LEAF and a Focus EV that has cooling. On 120 the Focus can either cool or charge but not both. So on a hot day in the sun you may get very little charging done. On 240 it blows and expels so much heat I can't park it in the garage, I have to leave it outside. I've tried to calculate the energy used for cooling but don't have a good method. In general it seems to be almost twice as much.
I have a Volt and it spends a fair amount of time cooling the battery, but it doesn't use anywhere near twice as much energy as my LEAF. Maybe 10-15% more. Considering the LEAF battery temp hovers in the 90s and the Volt is trying to keep its battery temp somewhere in the 70s, that's not too bad.
(Obviously, the hotter the climate, the more energy the car would use to keep the battery cool.)
Right now I am spending as much or more energy trying to keep my Leaf cool by air conditioning my garage as I spend on charging it. This helps somewhat in my mild SoCal climate, but it would be completely impractical in AZ. Obviously external cooling of the whole car (and garage) is much less efficient than a simple cooling loop threaded through the battery just like the car's charger has. I believe extending the existing cooling system to include the battery need not raise maintenance costs much.
The Tesla Roadster spent a lot of energy on battery cooling when the car was parked, but it looks like the Model S, with improved chemistry, only rarely actively cools the battery while parked and plugged in. They still have a very effective battery cooling system that gets used a lot while driving and Supercharging.