Hi, I have a 190ah LFP battery going in to an ammo can which will be in my truck bed. I'd like to heat the box using small ~25w heat strip(s) when the battery is too cold to charge, but only if it was going to charge in the first place.
What I mean by that, is that if it's the middle of the night and below freezing, don't bother because there's no sun to charge with anyway. Similarly, if I have a foot of snow on the panels and it's freezing outside, don't bother because the panels might not even produce enough voltage to initiate a charge cycle.
I was thinking some combination of the street light function, load ouput, and BMV low temperature relay setting could accomplish this. Likely easily with the ability to invert the streetlight functionality but I do not think that's possible from my research. Maybe some NC relay that the streetlight triggers when it'd normally be operating an actual streetlight (night?)
Any ideas appreciated!