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