Two 12V batteries wired in series for 24V will not stay matched. Small differences compound, one ends up chronically undercharged, and it fails years before it should - taking the healthy one with it because you replace them as a pair.

This fixes that for under fifty dollars, which is cheap against a set of batteries. If you are building the 24V system that makes induction cooking easy, put one of these in from the start.

Specifications
Balances two 12V batteries in series (24V) or four in series (48V with multiple units)
Alarm output
Manufacturer part number: BBA000100100