How to Balance Batteries in Series – Charge Each Battery Individually for Greater Performance & Lifespan

You can create higher voltage battery systems by linking 12 Volt batteries in series. Before linking batteries in series, it is important to charge each battery individually. This is known as balancing batteries in series, or voltage matching.
In addition to having a very long life (typically 5 – 15 years, backed by an 11 year warranty), Dakota Lithium Iron Phosphate (LiFePO4) batteries have twice the usable power of traditional batteries. We recommend that all customers balance their batteries before linking them in series so you get maximum performance and longevity.

Here’s directions on how you can balance your batteries in series:

1.To charge each battery individually, use a 12V Dakota Lithium or LiFePO4 charger (all Dakota Lithium batteries 50Ah or larger come with a free 12V 10Amp LiFePO4 charger). When charging, the LED light on the battery will turn red, and once it is fully charged, it will turn green. This only needs to be done once before you set up your system. You can later use a higher voltage charger to charge the entire system.
2.The batteries in the system are now balanced once all batteries are fully charged (24V, 36V, 48V, etc.).
3.It may be more convenient to use a Dakota Lithium or LiFePO4 compatible charger to charge the entire set in the future (for example, a 36V battery set can be charged with a 36V LiFePO4 battery charger).
4.Charging a single 12V battery pack with a 24V, 36V, or 48V charger is not recommended. A higher voltage charger is designed for charging a full set / series system at a high voltage. It is too much power for charging one battery pack.

Performance impact / benefit of balancing lithium batteries in series:

1.You can increase the run time of what you are powering by 10 – 20%
2.Battery lifespan is increased by 1 to 3 years depending on use.

Engineering explanation (why balancing batteries in series helps improve performance)

  • Dakota Lithium batteries (and all lithium or LiFePO4 batteries) are required to be shipped near empty and with slightly different voltages and charges in compliance with Federal DOT shipping regulations.
  • Before linking the 12V batteries in series, each battery should be fully charged and at the same voltage. This is called “matching the voltage”, or “balancing the batteries”, which increases the battery runtime and life.
  • When linked in series and charged with a higher voltage charger when near empty, the battery charger will read the system as “full” even if one or two other batteries are only 75% charged.
  • Even if the other batteries in the system are at 100% capacity, the system will only perform at 75% capacity if one of the batteries is at 75%.
  • Every time the system runs to empty, a single battery will be discharged to zero and experience higher stress, which results in a shorter lifespan.
  • You have ensured that your system performs at its peak by charging each battery individually before connecting them in series to create a higher voltage system.

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

It is important to balance your batteries after long periods of storage (>3 months) or if you notice significant performance declines.
Battery lifespan can be extended by balancing your batteries once a year.