Forum Discussion
BFL13
Oct 06, 2021Explorer II
pianotuna wrote:
BFL,
Where did 5C come from?
Trojan Trillium charging specs. Also some(all?) drop-in self- heating LFPs have the battery charger (there is your generator requirement) power the internal battery heater and get the bank up to 5C before it switches the charger power over to battery charging. It takes about two hours to warm them up from -20C to 5C I saw somewhere, but not so long when it is just under freezing of course..
The better idea is obviously to not let the batts get that cold in the first place, and the DIY set-up like time2roll has built should be way better than the drop-in method.
If the bank is inside the RV you keep it warm with propane furnace or if in outside compartment, you can perhaps DIY a way to get hot air or hot water (also from propane) to it, or else you are stuck with having some kind of DC heater.
Some say you can charge the LFPs at full blast once they are above 0C freezing, but others say you should/must use a reduced charging rate between 0 and 5C, scaling up the rate, like the Trillium specs.
Not many RVs will have a converter or charger that can do higher rate charging on a bigger AH LFP bank anyway.
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