Today I drove my Cmax 90 miles. I used the HVB piecemeal during the first 74 miles and the temp of the HVB reached a max of 71F. The outside temperature was about 56F.
I stopped at a 240v charger and plugged in the car to charge up the HVB. I sat in the car while charging. I noticed the HVB temperature going up during charging, as well as the fan inside the car was racing after some time (started out slow as usual). I charged it over an hour from empty to 60% on the HVB. The HVB temperature rose from 71F in front of me to 75F whiile charging.
Then I drove 16 miles back home 100% EV and drained the HVB back to 0%. The temperature rose further to 80F during this drive. When I got home the HVB was at 15.9% SOC and I always plug it in right away to recharge the hybrid battery as the charge level drops further when the battery cools and I don't want it to drop below 15%. So I plugged in the battery to recharge on 110v to bring up the hybrid battery back over 22%. That process on 110 took 32 minutes and during this time the HVB DROPPED from 80F down to 77F.
So what did I observe today? Like I always said, charging on 240v generates more heat inside the car which in turn raises the HVB temperature.
Charging on 120v makes less heat in today's conditions (fan in car on slow) and in fact actually lowered the HVB temperature. Now it could be possible the 80F is too high and while charging on either 120 or 240 and the temp was going to drop anyways to the upper limit closer to 75F given the OAT is 55F, but I still believe that 240 can warm up the battery while charging more so than 120v.
Edit: Just went down to check the HV battery, now at 73F and the charge dropped from 23% SOC that I brought it up to down to 19% now, a 4% drop in SOC due to the battery cooling down. That's why I do this, bring it back up some and then let it rest, I won't charge it up any more until tomorrow.
Edit #2: I plugged the HVB back in and charged it for another 22 minutes. The HVB went from 19% SOC to 24.3 SOC. The temperature of the HVB dropped some more from 73 to 71F. So what this is showing is that having the car plugged into 120v and charging is dropping the HVB temp due to the fan running, however, having it plugged into 240v earlier this evening raised the temperature from 71F to 75F.
This is what I am seeing with my Cmax, and this is what I expected or thought would be the case even without the tool to see it (scangage). Then it would make some sense that if you set value charge to start charging at say 10am that during the summer months plugging the car in when I get home in the evening/night would be beneficial to having the fan run all night without charging to cool the pack down, that is, if the garage temperature is actually cooler than the battery pack. If not its useless.
Edited by rbort, 25 April 2018 - 08:28 PM.