BATTERY CONNECTIONS: SERIES AND PARALLEL CIRCUITS

This article’s goal is to make you more knowledgeable about battery connections. It shows you how to connect your batteries in parallel or series configurations. For more instructions, continue reading below. Please get in touch with our battery specialists if you have any questions.

Series Connection : Voltage increases when a battery is connected in series.

When batteries are connected in series, the first battery’s positive terminal is connected to the second battery’s negative terminal, and so on down the string. To equalize the load, the interconnecting wires must have similar resistance and lengths. The charge current of each battery in the string will be the same, even though the voltage of each battery may differ.

When a single constant voltage charger is connected across the whole string, high voltage strings of batteries in series should not exceed twenty 6-volt or ten 12-volt batteries. Variations in capacity can lead to some batteries overcharging and others staying undercharged, which accelerates the aging process of batteries. Therefore, combining batteries of different capacities, makes, or ages is not advised.

You can see an example of this kind of battery connection in action in the following figure, which illustrates the series connection of two 12V 100 Ah batteries. This connection raises the system’s total voltage to 24 volts while keeping the 100 Ah capacity constant.

Parallel Connection : Capacity increases when a battery is connected in parallel.

Typically, batteries are connected in parallel to maximize capacity. The positive terminal of the first battery can be connected to the positive terminal of the second battery to accomplish this. The first battery’s negative terminal is linked to the second battery’s negative terminal in a similar manner. Batteries in a string connected in parallel will all get the same charge voltage during the charging process, but until equalization is reached, each battery’s charge current will differ. There are several uses for parallel battery connections, including UPS backup systems and electric scooters.

In the following figure, you can see an example of a parallel battery connection. It shows how two units of 12V 100 Ah batteries connected in parallel produces an overall output of 12V 200 Ah.

Important takeaway : When inter connecting batteries, there are a few important aspects you need to consider. It is vital to understand the requirements of your application and connect. Always follow the recommended guidelines for your application. Do not ever use two different chemistries when connecting multiple batteries together. For example, never connect an AGM battery with a flooded battery. This is because the voltages of the two batteries will be different. More importantly, the charge rates will be different and the capacities may be different, thus resulting in a shortened life span. It is always best to match capacities as much as possible.