I would like to have an inexpensive simple Ampere Hour Meter for a 12 volt system with a widely varying max flow of 150 amps and a counter. The system does not need to be terribly accurate so need not make provision for varying charge voltage, in fact it need not measure amps exactly just some arbitrary unit of accumulated charge. It does however preferably need to count UP on charge units and count DOWN on discharge units leaving a net charge/discharge value.
I would prefer it to work with a current shunt already in place ( 200 amp 75 mV) and I would prefer to purchase an inexpensive ready soldered module(s) to achieve this. I have thought of possibilities such as a linear voltage to frequency converter but would really like the input of you guys to keep it simple and inexpensive. Accuracy is not as important as repeat-ability as I can use a table correlated to acid specific gravity to obtain meaningful numbers from any arbitrary count.