Connecting Batteries in Series or in Parallel: Which Is Better?

Connecting the batteries in your solar battery bank can increase the voltage, amperage, or both, of your bank’s energy. When constructing a battery bank with Victron Energy solar batteries, you have 2 options: connecting them in a series or in parallel. What’s the difference between these 2 forms of connection, and is one better than the other? Keep reading to find out.

Connecting in Series

To connect batteries in a series, connect the negative terminal of the first battery to the positive terminal of the second using a jumper wire. Then, use another cable to connect the open terminals to your system. Never connect the open terminals back to one another; this can short circuit the batteries and cause damage.

If you have multiple batteries, just continue connecting one battery’s negative terminal to the next battery’s positive terminal until you reach the end of the line. Essentially, you’ll be making a long line connecting negative to positive, then will complete the circuit by connecting the end terminals on each side to your application.

Benefits of Series Connection

Connecting batteries in a series adds the voltage of the batteries in the bank, but the amperage rating remains the same. So, if you have 4 separate 6-volt batteries joined in a series with 10 amp hours each, your bank will produce 24 volts, but will still have a total capacity of 10 amps. Make sure the batteries you connect have the same voltage and capacity rating; if they don’t, you could end up shortening the life of your batteries.

Connecting in Parallel

To connect batteries in parallel, connect the positive terminal of one battery to the positive terminal of the next, as well as connecting the negative terminals to one another. Then, connect the end terminals to your application to ensure batteries drain equally.

Benefits of Parallel Connection

A parallel battery connection does the opposite of a series connection: It increases the amps but the voltage remains the same. So, with the same example as above, you would have 40 amps, but only 6 volts.

Parallel and Series Connection

If you have at least 4 batteries, you can connect in series and parallel to increase both the amps and the voltage of your battery bank. Just connect negative to negative and positive to positive on the first 2 batteries; then, connect the positive terminal of the second battery to the negative terminal of the third, and repeat the connection pattern outlined above. Connect the end terminals (one positive and one negative) to your application.

If you have more than one Victron Energy battery, make sure you connect them in the format that meets your needs best.