Hello , A reserve capacity related to the amount of time a battery can deliver 25 amps to a load before the voltage drops below 10.5 volts for a 12 volt battery and I thinks 4.4 volt for a 6 volt battery at 70 deg starting with a full charge. So that battery would last for 113 mins at 25 amps draw before the volts dropped below the cutoff voltage.
The voltage delivery is non linear , A lead acid battery will discharge with a fairly even loss of voltage over time, Then there is the transition point where the voltage drops off quickly over time. This will graph out differently for each battery. The drop out voltage is different between battery types.
The battery configuration has a great effect on the efficiency of the storage pile. But the total energy will remain the same- Let me explain. An inverter needs to have a input that has a consistent voltage. As the voltage drops the inverter draws more current. The increased current causes more heat to be made. The heat is lost power. You need to configure the batteries to provide voltage and current over time and reduce parasitic losses to heat.
A battery pile needs to be balanced to provide current and voltage over time for the expected loads. This can be done many ways using parallel and series batteries. The use of two or three inverters have advantages and dissadvantages. You will need to calculate your power consumption and figure in idle time .
I recommend you look at the information that's availible on line. Try the "free sun power" web site. They solar energy web sites are the leading edge of the inverter technology. They charge batteries then use inverters to convert to a/c . You will find so much info on batteries, inverters , distribution , load calculations and the like to keep you busy for hours. These sites have the knowledge on the latest . You may find that it easier than you think. Please Click Accept, Thanks Again. Scott