[dcb]

but you do need at least two voltage monitors to get a first order (extremely coarse) balance monitor.

edit apparently the jld404 isn't isolated either, so you would need two of them and two isolated dc-dc. or you can reference both to ground but that will create an imbalance over time with the lower pack half having 2x the leakage current.

http://www.electricsubaru.com/fuelGauge.html