The capacity of your two GC 6v’s (connected in series to form one large battery) should be 215 amp/hrs because the amps are divided by two when the voltage is doubled...Versus the 85 or so amp/hrs of your previous group 24...And if you consider that your usable amp/hrs for most wet-cells is to about 50% of capacity (without causing long term damage), you gained about 65 amp/hrs additional capacity...
Per your example, it doesn’t sound like you’re using too much power, and consider that 12.6+ v is fully charged and 12.5v = 90%, 12.4v = 80% and 12.3v = 70% SOC (state of charge)...
Check to see what your charger is rated at...Mine is rated at 45 amps and does a ok job of charging my GC’s, but I also have a 100a pass-thru inverter/charger that (though a bit oversized) works better.
For instance (though not too scientific) this morning my two GC’s were down to about 71% SOC (per LinkLite meter and shunt) and when I kicked on the 100a charger, the amps started out at about 39a then began to slowly taper off (over a few minutes) to what was seemingly the apparant acceptance rate of the two batteries...
When I started out with the 45a factory converter-charger, the amps were only at about 14.5a which would mean I’d have to run the portable genny for quite some time...
