How to Balance Batteries in Series

What is Balancing?

Battery cell balancing involves equalizing voltages and state of charge across cells, particularly when they reach a full charge. It's important to note that no two cells are exactly identical, as there are inherent variations in factors such as state of charge, self-discharge rate, capacity, impedance, and temperature characteristics. These distinctions persist even if the cells are of the same model, from the same manufacturer, and product lot.

The primary objective of cell balancing is to ensure an equal distribution of voltage and state of charge across all cells, particularly when they reach a fully charged state. Cell balancing can generally be classified into two types: 

Charge Each Battery Individually for Greater Performance & Lifespan

Before linking batteries in series however it is helpful to first charge each battery individually. This is called balancing batteries in series, also known as voltage matching.

1. Use a 12V Lithium or LiFePO4 compatible charger to charge each battery individually. 
2. The LED light on the battery will be red when charging and will turn green when the battery is fully charged. You only need to do this once before you set up your system. In the future you can charge the entire system with the higher voltage charger.
3. Once all batteries are fully charged you can install them in series to create a higher voltage system (24V, 36V, 48V, etc.). The batteries in the system are now balanced.
4. When charging in the future it may be more convenient to use a higher voltage Lithium or LiFePO4 compatible charger to charge the entire set when linked (for example, a 36V battery set can be charged with a 36V LiFePO4 battery charger).
5. Do NOT use a 24V, 36V, or 48V charger to charge a single 12V battery pack. The higher voltage charger is only for charging the full set / series system at a high voltage. It is too much power for charging a single 12V battery pack.

When should I balance my batteries in series in the future?

1. Balance your batteries after long periods of storage (>3 months), or if you see a significant performance drop.
2. Balancing your batteries once a month will extend the battery lifespan.