[see
Forum Thread this is taken from for more]
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:
- Do a discharge capacity test with a shunt. Record capacity in watt hours.
- 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
- 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)
- Bottom balance the cells
- Charge the cells at a .2C rate
- The moment a cell hits 3.6V while charging, record the pack voltage
- 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).