wingnut

Make sure the fan behaves the same, if not then consider adding an external one like a 12V (24V) PC fan. Sometimes the charger thinks the battery is full after a session because the voltage is higher than lead acid and doesn't go into bulk (fan on) charging but rather float (fan off), but still draws max amps causing it to over heat. The mecer trolley type (IVR-1200LBK/Ivr-2400lbks) has this behaviour, not sure about this one though.

I assume 12100 means a 12V 100Ah LA replacement?

Normal range for LFP is 2.5V-3.65V (10V-14.6V) per cell. If you have the luxury of setting your own voltages, this is what I would use: BULK: 14.1V (if you can set absorption time then make it 1 hour) FLOAT: 13.4V LOW CUT: 12V (or 11.5V if there is a heavy load) CHARGE CURRENT: less is more but anything up to 1C (100A). Recommend: 20A.

Why even bother balancing if only going to 3.45V?

What about 4 of these? 2 series strings in parallel would give you 5120Wh of storage. You would need a balancer like this.

@Abe53 Please share the love and let us in on your secret of getting 18650's for almost free?

Surely it's normal LiFePO4 voltages? 12V values (x4 for 48V) BULK 14.6V (lower for less wear and tear, 14.1V is the sweet spot for capacity and charging speed imho) FLOAT 13.6V (disable if possible or go even lower like 13.4-13.5 or work out what the battery resting voltage is) Charge current 0.5C