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How Do Lithium Ion Chargers Work?

Batteries Plus Blog - Power - by Joe Weber - updated on 9/16/2022

NOCO Genius charger and X2Power Lithium battery

Chargers are not all the same and are not a one-size-fits-all product. Lithium batteries like our X2Power Lithium Marine Deep-Cycle or our X2Power Lithium Powersport lines need to be paired with a charger designed specifically for lithium. A good battery charger is key to ensuring that your lithium batteries are always charged and will perform well after a charge. But what makes a lithium charger special?

How Do Lithium Battery Chargers Work?

A Lithium Iron Phosphate (LiFePO4) battery uses the same constant current and constant voltage as a lead-acid battery. While they are similar, the chargers for lithium batteries function a little differently. While lead-acid batteries require 3 charging stages, lithium only requires 2.

Lithium Charging Stages

  • Stage 1 is your constant current stage and accounts for roughly 80% of the battery's state of charge. This stage of charging is maintained by sending a constant, relatively high current to the battery.
  • Stage 2 is a constant voltage stage. Once the battery reaches its voltage limit of 14.7V the charger holds the voltage constant and reduces the current gradually down to 0 until the battery reaches a full charge. At this point, the battery is charged to 100%.

Where lithium batteries differ from lead batteries is that they don't require a float charge stage like lead-acid batteries. A float stage is a charging process that keeps the battery at 100% charge while in storage. Dedicated lithium chargers will not have a float stage in the charging process. Lithium batteries have such a low rate of discharge that they can be left in storage for long periods without requiring a float charge stage.

Our recommendation is to look for a charger that is compatible with all battery types to avoid needing to have multiple chargers. One charger that works with multiple batteries is always better than one for each battery. Take a look at our large selection of chargers that work with lead-acid as well as lithium.

Can I Charge a Lithium Battery With an AGM Charger?

It is safe to use a lead-acid charger with a lithium battery but you need to take a few things into consideration.

If you are planning on using a constant voltage lead-acid charger make sure the charger meets the following conditions:

  • Lithium batteries do not sulfate and the charger must not have a desulfating setting.
  • The Constant Current/Constant Voltage charging has a voltage of 14.7V.
  • Lithium batteries don't require a float charge but if the charger has a float charge mode it must have a voltage of 13.8V.

What Charger Should I Buy?

If you have a lithium battery that needs charging, look no further than your experts at your local Batteries Plus to help you find the best charger for you. We have a large selection of chargers for lithium, AGM or flooded lead batteries for your powersport toys. If it's time for a new battery we carry an extensive selection of batteries for your motorcycle, ATV/UTV, jet ski or snowmobile. If you'd like to learn more about how battery chargers work read our blog article titled "How Do Lead Acid Battery Chargers Work?"

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