Apologies if my search missed the answer already; what's the ideal upper temperature for a 9.52 kWh battery? I followed several discussions recommending insulation to keep the battery from getting too cold and in the autumn last year I surrounded the battery with a Kingspan box. This has kept the battery warm (>15C) through last winter. Today I noticed that it hit 34C and I can't find a recommended maximum so I'm concerned that it might be a bit too warm...
Monty there are actually two battery temperatures, the BMS (battery management system) temperature and the battery cell temperature. The BMS temp can easily get to 60 degrees when the battery is charging or discharging hard, but soon drops when the load comes off. The cell temperature moves more slowly with outside air temperature.
Looking at my 9.5 thats inside in the garage, the BMS went between 20 and 60 degrees today and the cell temperature between 26 and 36.
Sounds like yours is not too hot, I’ve not heard of anyone needing to add extra cooling to their batteries
geoffreycoan Thank you for your reply. I will have to look at which temperature I am monitoring (and add a meter for the other). The battery is in a cool place so in hot weather, cooling will be just a matter of removing the insulation.
Monty.
I think the battery starts derating when cell temperature hits 40C - or possibly 45C, can't remember TBH, its listed in some firmware notes IIRC.
In general anything over 40C is going to reduce cell lifespan and probably quite dramatically once you hit 50C.