INCREASING CAPACITY THROUGH SERIES AND PARALLEL CONNECTIONS
What is the difference between series battery connections and parallel battery connections and how do they increase battery capacity and voltage?
Originally Posted by twinboat
All of the advice you gave was good with the exception of the above statement.
2, 6 volt batteries in series, double the voltage but not the amp hours.
With only 2, 6 volt batteries the 50% capacity will be 110 to 115 AHs.
In the SERIES CONNECTION, batteries of like voltage and Amp-Hour capacity are connected to increase the Voltage of the bank. The positive terminal of the first battery is connected to the negative terminal of the second battery and so on, until the desired voltage is reached. The final Voltage is the sum of all battery voltages added together while the final Amp-Hours remains unchanged. The bank's Voltage increases while its Amp-Hours, Cranking Performance and Reserve Capacity remain unchanged.
In the PARALLEL CONNECTION, batteries of like voltages and capacities are connected to increase the capacity of the bank. The positive terminals of all batteries are connected together, or to a common conductor, and all negative terminals are connected in the same manner. The final voltage remains unchanged while the capacity of the bank is the sum of the capacities of the individual batteries of this connection. Amp-Hours Cranking Performance and Reserve Capacity increases while Voltage does not.