I've read the battery is cooled by the cabin ac. I am one of those freaks who likes it warm even in the summer. I have my ac set to 78 sometimes even if it is in the upper 80's I will drive home without the ac on. so that begs the question, how hot is too hot for the battery?
Sorry - there is no real answer. It has a lot to do with the heat generated when the battery is charging. If you don't have long uphill and downhill runs then you are probably OK with that 78 degree temp setting. Is your area of Texas relatively flat? I once had my 2010 Prius refuse to use the battery after I let it sit in 100 degree weather after a quick 1000 foot elevation drop. After a quick dinner I returned uphill using the ICE only. I had no spot to pull off the road until I had gone a few miles. Thank god after I restarted the car thinks got back to normal.
it is fairly flat where I live, some rolling hills (read that elevation changes) of perhaps 50 or 75 feet or so but nothing I would really refer to as a hill. I appreciate the reply. In this part of SE Texas the ambient temperature can reach 100 or better, with the windows up probably above 130 in the car.
xpc has it right, if it's too hot, the computer will shut down the battery. however, your tactics will probably reduce the life of your battery to some extent. you should get a scan gauge to monitor battery temps.
I'm using a Scangauge to monitor battery temp. Out of the box SG won't show this, but by entering an "XGauge" you can add this capability. You want to monitor sensor #2. There's 3 sensors along the battery: #2's in the middle, and tends to be hottest I've heard. I think you're doing just fine, IMO: 1. 78F is a fine sweet spot to run AC 2. The use of AC to protect the battery is overated. I use AC very infrequently, don't see much of a correlation between its use and lower battery temps. Even on cool evenings on an extended drive, battery temp does climb, typically settling around 35~38C. In hot, stop-and-go I've seen it get up to around 45C.
I sat idling in my C for an hour last week while waiting for someone at a doc appt. It was in the shade using A/C (lending creedence to Mendel's #2 contention above), but outside temp was just above 100F. On a subsequent drive that ensued, the batt. fan came on at full speed and wouldn't stop. This is the first time I'd heard it. Moral of the story is I won't leave the poor thing idling for that extended amount of time in the heat of summer again. I really hope one of these ODB2 scanners can measure the battery temperature. I would much rather use my phone since I already have it in the car when en route.
