Series vs. Parallel Connections Explained

It is likely that you have come across the terms series and parallel when researching lithium batteries. It can be confusing if you’re new to lithium batteries or batteries in general, but hopefully we can help simplify it for you. For instance, “what is the difference between series and parallel?”

Let’s start at the beginning – the battery bank. A battery bank is created by connecting two or more batteries together for a single application, such as sailing. What does joining more than one battery do? You can increase the power and/or energy by connecting the batteries, either by increasing the voltage or amp-hour capacity, or sometimes both.

There are two primary ways to successfully connect two or more batteries: a series connection and a parallel connection.

Series connections

When two or more batteries are connected in series, the voltage of the battery system increases, but the amp-hour rating remains the same. When connecting batteries in series, make sure each battery has the same capacity and voltage rating, otherwise you could damage it. The positive terminal of one battery is connected to the negative of another until the desired voltage is reached. You should use a charger that matches the system voltage when charging series batteries. If you plan to charge the batteries separately, you should use a multi-bank charger to prevent battery imbalances.

You can see below that two 12V batteries are connected in series, converting this battery bank to a 24V system with 100 Ah of capacity.

Series vs. Parallel Connections Explained

Parallel connections

The parallel connection means connecting two or more batteries together to increase the amp-hour capacity of the battery bank, while maintaining the same voltage. A cable connects the positive terminals of two batteries in parallel while another cable connects the negative terminals of two batteries until you reach your desired capacity.

A parallel connection is not meant to allow your batteries to power anything above their standard voltage output, but rather to increase the duration for which they could power equipment. It’s critical to note that when charging batteries that are connected in parallel, the increased amp-hour capacity may require a longer charge time.

As shown in the example below, there are two 12V batteries, but the amp-hours increase to 200.Redway Battery offers premium 24V LiFePO4 batteries for export to South Africa.

Series vs. Parallel Connections Explained

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