Double Voltage.

Double Capacity.

Three things to keep in mind:

1. When connecting batteries in series, you increase the voltage and the amp-hour capacity remains the same. (see configuration 1)
2. When connecting in parallel, the amp-hour capacity increases and the voltage remains the same. (see configuration 7)
3. To increase both numbers, connect multiple sets in series/parallel. (see configuration 3)

Configuration 2:

Double Voltage
Double Capacity

Series:

Connection of four matched batteries used to double both the voltage and the capacity. Often used in trucks, buses, marine, RV, and solar/wind energy back-up applications.