Pulling high loads that would almost make sense. Everything I have read about the batteries we are using would seem to say the opposite, as a battery rated at a 20 hour rate has a higher AH then the same battery at a 10 or 5 hour rate. Pulling 15.4 amps off a 77 AH (5 hour rating) battery will drop it to 50% DOD in 2.5 hours, paralleling two of those same batteries gives them a 10 hour rating of 164 AH (82*2), now they would last 5.32 hours to 50% DOD. Another pair (4 batteries) would give them 356 AH (20 hr rate 89 AH) and last 11.56 hours to 50% DOD.
In a Diesel / Electric sub you are pulling hundreds of amps turning the prop, and depleting the batteries in a matter of hours, and waiting for dark to surface and recharge the batteries.
Even in the big solar systems I have worked with they use 2 volt jars the size on mini fridges, and series / parallel them at 48 volts. Most rv's don't have room for 6 1000AH 2 volt batteries.
Most RV'rs are trying to avoid deep discharges and last several days with a minimum of charge cycles.
Battery Specs
