By Gareth Downes‑Powell, Updated March 24, 2022.
When you need more voltage from a set of batteries, wiring them in series is the simplest approach. In a series connection the individual voltages add together while the capacity (amp‑hours) stays the same, allowing you to drive higher‑voltage circuits without changing the current supply.
Commercial high‑voltage batteries are often made by linking lower‑voltage cells in series. For instance, a 6‑volt pack can be created by connecting four 1.5‑volt cells end‑to‑end.
Cut a ~6‑inch length of copper wire and strip about ½ inch of insulation from each end with a wire stripper.
Attach one stripped end to the negative terminal of Battery A, and the other end to the positive terminal of Battery B. This links the batteries so that the negative of the first is bonded to the positive of the second.
With a multimeter set to DC volts, touch the positive lead to Battery A’s positive terminal and the negative lead to Battery B’s negative terminal. The meter should read the sum of the two cells (e.g., 3 V for two 1.5‑V cells).
To expand the stack, run a wire from the negative terminal of Battery B to the positive terminal of Battery C. Measure the total voltage by connecting the multimeter’s positive lead to Battery A’s positive and the negative lead to Battery C’s negative. For three 1.5‑V cells, the reading will be 4.5 V.
When wiring batteries in series, use identical cells so they discharge evenly and avoid mixing capacities or chemistries.
Never connect like terminals together. Always join a negative terminal to a positive terminal to prevent short circuits and potential damage or injury.
