It's been kind of implied here but maybe not said exactly, but if you are serious about monitoring battery condition and the exact current (draw, in amps) on your battery bank, a power monitor using a shunt in series with your batteries is the best feature you can add. When the batteries are charging or discharging you can see the current due to whatever devices are currently connected. It's a great way to spot that some component of the RV is drawing current when you didn't expect it also.
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