Quoteop-amp that has a very high common mode voltage rejection ratingI thought about something like that, but it requires much more circuitry [45 opAmps,plus etc] than the other approaches. But would be very good for a few sample points only.
op-amp that has a very high common mode voltage rejection rating
45 DPST relays
Check out the linked pdf doc.
separate Arduino processors, powered at different points in the battery chain, and each reading 6 A/D channels,
Or just one with a 2 pole 45 throw switch ahead of the opamp.
A balancer type does more than just measure individual cell voltage.
relays for computer logic gates.
and 4 Megas
We did an entire runway lighting control system with relays once, 1000s of them in 19" racks, all plug-in modules with NAND, AND, OR, flip flop etc functions and all at 48 volts.It was destined for an Asian country (Malaysia I think) and the design brief was that it had to be simple technology that the "natives" could fix.