LiFePO4 Charge Profile Parameters

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  • 12V LiFePO4 Battery w/ BMS:
    • Absorption: 14.5V
    • Float: 13.6V
    • Inverter Cut-off: 10.7V-12V (depending on size of load and voltage drop etc)

    24V LiFePO4 Battery w/ BMS
    • Absorption: 29V
    • Float: 27.2V
    • Inverter Cut-off: 21.4V-24V

    48V LiFePO4 Battery w/ BMS
    • Absorption: 58V
    • Float: 54.4V
    • Inverter Cut-off: 42.8V-48V
    Individual 3.2V LiFePO4 Raw Cell (for individual cell capacity testing)
    • Absorption: 3.625V
    • Float: 3.4V
    • Low voltage disconnect for capacity testing: 2.5V

    If you are using a BMS and wish to manually cycle up to 90% SOC:
    1. Do a discharge capacity test with a shunt. Record capacity in watt hours.
    2. Charge slowly up to 90% SOC (take capacity Wh figure and multiple by .9), and while charging, record the voltage right when it hits 90% SOC
    3. Set the absorption for all chargers in system to the voltage you recorded in step 2
    5,000+ Charge Cycle Absorption Recommendation
    If you want your LiFePO4 cells to last a long time, you can set your absorption to Victron's custom LiFePO4 charge profile recommendation:
    • 12V Battery: 14.1V
    • 24V Battery: 28.2V
    • 48V Battery: 56.4V
    You can pull full capacity with the absorption figures above, but the charge rate will be reduced at high SOC.

    If you are not using a BMS (not recommended, for advanced users only)
    1. Bottom balance the cells
    2. Charge the cells at a .2C rate
    3. The moment a cell hits 3.6V while charging, record the pack voltage
    4. Manually set absorption for all chargers to the voltage in the previous step

    If you are using used LiFePO4 cells w/ varying internal resistance readings, charge up to 3.525V per cell (12v/24v/48v absorption: 14V, 28V and 56V).
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