Itinerant1 wrote:
One more thought that seems to be parroted is the temperature. When talking about 0c/ 32f its the cells (batteries) temperature not the ambient temperature that's the end all be all of charging and as mentioned hopefully the cells have the cut off to charging from the bms.
Cutting off early morning charging from solar when it's below ambient freezing temps is crazy especially during this time of the year as the day light get shorter and the arc of the sun is lower. Precious charge is wasted if your controller can turn off charging and battery cell temps are above 32f.
I've been in 17f ambient temps, cells showing 38-40f (I can see all 20 cell temps and my bms/ ems can) solar charging at 20-30a and carrying my misc loads. This can extend the need for hooking up the generator for hold over charging, right now with the shorter daylight and my daily "wants", we're 21 days in partial solar charge living of 35% - 92% SOC. As long as my SOC is 60-65% by sundown that leaves enough to run the furnace use the microwave for dinner and breakfast, make a couple pots of coffee, toaster, humidifier usally going 24/7 and charging the phones, tablets and laptops all before the sun comes up. This is going into the 7th winter season fulltime living like this. ;)
this is what I have found this fall also. becasue I was running the furnace the draw on my battery was able to keep the cells much warmer than the space it was in. so in the morning the battery itself was still well above freezing. that and charging will also warm the battery up its self, the question is would it be enough. I think his idea with a yetti cooler and a small silicone heat pad will do the trick. that yetti will keep a block of ice for 11 day in plus 30C weather. haha
