If you’re up for a long read, check out this thread about my variation on the poor mans multilux. Might contain some useful bits. The biggest problem you run into is that the voltage difference between charged and uncharged series batteries is more than the chips alone can handle when using more than 3s with modes and adding a dropping resistor reduces in spec run time unless you also add an additional switch to cut out the high wattage resistor partway through the discharge cycle. That said, I’m happy with my results so by all means, carry on and let us know how it goes.