Advice on Lithium Solar setup

brulaz wrote:

Battleborn says that while you can charge up their LiFePO4 cells at lower voltages, maybe as low as 3.4V per cell (13.6V for 4), you want to go higher to *balance* the cells, up to their recommended 14.4-14.6V. The balancing is strictly a BMS function and the BMS balancing procedure controls the individual cell voltages.

So what happens if you have only weak solar or alternator V's that never get up high enough to balance the cells? :(

Every BMS is different. "Normally" it needs voltages corresponding to +90% SOC to get it balanced, some BMS do this at 91% and some at 99%.

This is why it is "sometimes" necessary to charge over 90%, carefully.

This is why you want a charger with easily controlled voltage. Ideally, it should have 2 profiles set - 90% for daily charging and 100% (or whatever is necessary) for balancing once a week or so. There is no need to balance it every day: Balancing

I would also like to choose my charging current and to start at lower current, increasing it later. Something that advanced e-bike chargers do, but automotive 12V chargers don't.

There are many 12V, 36V and 48V boxes packed with 18650 LiFePO4 cells, btw. They don't bother to tell you cells size, only chemistry and approximate voltages.

brulaz wrote:
on another forum there's a guy who said he can still pump 20A into a 300Ah LifeBlue battery after it reaches 100% SOC and his charger's V drops below 14V (EDIT: actually his weak solar charger never gets up that high)

Could be poorly controlled experiment, SOC way below 100%. Hard to tell without knowing the details.