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How to charge LiFePo4

LiFePO4 does not need a multistage charging profile.

The manufacturer of our 100 ah cells, and the MFG of the common 280ah cells specifies charging at a rate of 0.5c up to a maximum voltage limit of 3.650 per cell.

Based on the LiFePo4 charge curve the cells will reach nearly 100% charge at 3.500v per cell, so this is our recommended target voltage (14.0v per 4-cell battery, 28v per 8 cell battery).

Note that there is no mention of “float” charging. This is only applicable to lead acid yet most charger designs include a float setting for LiFePo4, usually 13.2v for a 4 cell battery.

Why is this a problem? Because at 13.2v the battery will be significantly discharged, and so you will observe the battery going through a deep cycle after every full charge, even though it remains plugged into shore power.

Therefore the ideal charger for LiFePo4 batteries (in our opinion) is a current limited power supply set to 14.0 to 14.2 volts.

3 thoughts on “How to charge LiFePo4

  1. Does C rate of charge matter other than how long it takes to charge? I have a 16S/48V setup with 280Ah batteries, and it is not easy to charge at 0.5C, which is 140A. Is there an issue if my C rate of charge is, say 0.1 or less? I haven’t any panels yet and I’m using a power supply. Your BMS is also just 100A. Must I charge them in groups of 12 volt or 24 volt? Thanks for any help.

    1. A slower charge rate is always acceptable. The quoted C-rate is the upper limit.

      You will need a charger for a 48v system. The upper limit voltage should be set to 56.8v.

  2. Generally a charger will stop charging at .05C (5%). That would be 14 Amps for a 280Ah battery. What happens if my solar panels are only charging @3-5 amps, won’t this overcharge the battery?

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