Historians believe Benjamin Franklin christened pairs of cells ‘batteries’, in 1749. America was passing through a time of conflict, and they reminded him of artillery cannons ready to engage the enemy. Series and parallel battery connections enable us to manipulate voltage and capacity, improving their effectiveness. We could say they were an essential key to their success.
Connecting Batteries in Series or Parallel
The potential of an energy source on its own is strictly limited. Franklin would have known the difference between a one-horse, and two-horse buggy. It was common knowledge a pair would go faster, or cover longer distances. Series and parallel battery connections achieve something similar.
Batteries in Series
Batteries in series have their opposite terminals connected together as we illustrate in our first image. This creates a simple circuit where their combined voltage increases, but their endurance remains the same.
So, if for example we joined two fully-charged 6-volt lead batteries in series, then they should produce 12-volts. However, they would go flat in the same time as a single one would.
Batteries in Parallel
Batteries in parallel have their like-to-like terminals connected together, as we illustrate in our second image. The net result is the endurance (capacity) multiplies, while their voltage stays the same.
So if for example we joined two fully-charged 6-volt lead batteries in parallel, we should still get 6-volts. Although the pair should last twice as long as a single one.
Different Combinations of Sets of Batteries
It quite often happens we need to increase both battery capacity, and voltage at the same time. A combination of series and parallel battery connections helps us achieve this goal. However, we should only use matching batteries of identical ratings, and in the same state of charge.
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