Why is the Current in my LFP Battery Disappearing while Charging?

Problem

If the battery current disappears when charging, possible causes for this problem are:

• The battery has overheated, enabling over-temperature protection.
• The battery pack is out-of-balance.
• Charger voltage is too high.

Solution

To resolve situations where current disappears when charging:

1. Allow the battery to cool.
2. Disconnect and apply a 14.0 V charge voltage (for 12V LFP Batteries) for 48 hours to balance the charge on all cells, especially any cells reading a lower voltage, even if the difference is small (<0.005mV).
3. Ensure charger voltage is set to 14.6 V or less, verifying accurate voltage output with a multimeter where possible. If the problem continues to occur, reduce charger voltage and leave topped up for 48 hours of balancing. If the problem persists after allowing cells time to balance, reduce charger voltage.
4. If using a Lead-acid charger: Ensure charger is not performing maintenance such as equalization or entering a float voltage above allowable voltage range. Ensure temperature-based voltage compensation (which should not be used with LFP batteries) is turned off. If you cannot reduce the charger voltage, a new charger may be required.
5. If cells are nearing or past their end-of-life, stored improperly, or were subject to operation outside their intended conditions, capacity imbalances may be present, causing charging to be stopped consistently. If this is the case, batteries can still be discharged and cycled if charging is interrupted, however the imbalance will limit the overall capacity of the pack.