Electrical components like batteries and solar panels can be used independently or combined. If combined, they are connected in series or in parallel.((more complicated arrangements are possible; see below))
Series** connections **double the voltage while the current (or capacity in Ah when dealing with batteries) remains unchanged.
- common example: 2 6v, 200Ah golf cart batteries in series = a 12v, 200Ah battery bank.[1]. This is a recommended configuration.
- less common example: 2 12v, 90Ah batteries in series = a 24v, 90Ah battery bank.
Parallel** connections **double the current while the voltage remains unchanged.
- common example: 2 12v, 90Ah batteries in parallel = a 12v, 180Ah battery bank. This is not a recommended configuration. It is not due to any shortcoming of parallel connections; 12v "deep cycle" or marine batteries are rarely real deep cycle batteries and suffer from the treatment van life dishes out.
Wide parallel configurations (like 4P) are difficult to charge/discharge evenly without exotic cable configurations.
notation
When discussing multi-battery banks it is common to describe the electrical layout with a particular notation.
p = parallel \\ s = series
Examples:
- 1p1s - a single battery
- 1p2s - two batteries in series, as one finds in the common 2x6v GC battery setup
- 2p1s - two batteries in parallel
- 2p2s - two sets of batteries in parallel linked in series as one finds in higher-capacity GC-based setups