Parallel Batteries Versus Batteries Wired in Series

Updated 06/18/2016 | Published 06/16/2016

Question:

My dealer installed two batteries in parallel, but the positive lead goes to one battery and the negative lead goes to the other battery. Is this going to be a problem?

asked by: Tom

Expert Reply:

If two batteries are wired in parallel, the positive terminals of each battery will be connected together, as will the negative terminals. Assuming both batteries are 12 volt, you'll have a 12 volt output but there will be more capacity.

If the batteries are wired in series, the positive terminal of one battery will be connected to the negative terminal of the other. This would double the output of the batteries, assuming each battery is a 12 volt, wiring the batteries in series would provide 24 volts of output.

If the batteries were SUPPOSED to be wired in parallel but were incorrectly wired in series, the electrical system of the vehicle could be damaged.

expert reply by: Mike L