Maximizing Battery Life

I am using an AC300 with 1 B300 battery to power off-grid cabin. Unfortunately, I do not have solar panels yet, but charge it up with a generator. Because I currently do not have it tied into the main panel, I still use a generator for well pump and other high amp items, but will eventually fully integrate it. Is it best to let the battery run down to ~10% or something similar prior to recharge? If I leave the charging cord plugged in it will charge every time I turn on the generator for whatever reason and I may charge it randomly at ~50-90% depending on last time I needed to turn on the generator.


I have two AC300 and B300 units and I leave then charging all the time. When the B300 battery is fully charged, the AC300 will not overcharge the battery, but may consumes a few watts per hour while on. You should try to operate the AC300 in UPS mode so the cabin will take its power from the AC300 all or most of the time. If the main power fails, the AC300 will continue to supply power until the battery runs down.

Thanks for the feedback. To clarify I guess I am less concerned with overcharging as much as what consumes a lifecycle of a battery. I forget what Bluettie says the lifecycle warranty of the B300 is, ~3500 cycles but what does that mean. For example, if I charge from 90%-100% or 10%-100% are they both 1 lifecycle or ~1/10 cycle and ~1 cycle respectively. I apologize for my ignorance but given the price of batteries, I want to utilize them in the most efficient manner.

I’ve always heard that a cycle is one full discharge and then a full recharge. Partial cycles count as a percentage of one cycle and micro cycles (float) don’t count as any. Sorry I don’t have a reference but it’s probably out there somewhere.

Temperature (particularly heat) influences degradation of LiFePO batteries more than cycles, so make sure you keep them out of hot places like the attic or direct sun. Cycling degradation happens more at the 0-30% level of charge than higher levels, so you probably want to keep it above 30% as much as possible. Keeping the cycling in a narrower band of charge also extends life, so if you could keep it between 30% and 80%, say, you may get the best bang for your buck.

The cycle counts you read about are for full cycles (100% to 0%), but the actual degradation patterns are little more complicated than pure cycles.


Overall, though, these batteries should have much longer lives than standard LiOn batteries. I suspect in 10 years when we might start to notice degradation, we will be tempted to replace them with something even better and cheaper anyway…


I appreciate the thorough with references, Thank you!