The flat curve changes the job
Across most of the usable range a LiFePO4 cell barely changes voltage, so state of charge cannot be inferred from voltage alone and small measurement errors translate into large apparent differences between cells.
What to specify
Series count and continuous current come from the pack and the load. Beyond that, temperature sensing placement and low-temperature charge cut-off matter more on LFP than the headline current figure.
- Series count, matched to the nominal system voltage
- Continuous current taken from the load, with headroom
- Temperature sensor placement on the cells rather than the board
- Low-temperature charge cut-off, which LFP needs and lead-acid habits ignore
Commissioning a new pack
Top-balance the pack before the first full cycle. A pack assembled from cells at different states of charge will look unbalanced under load no matter how the BMS is configured, and the balancer will spend a long time correcting what an hour of preparation would have avoided.
Official next steps
Frequently asked questions
The voltage curve is flat across most of the usable range, so voltage alone does not indicate charge.
Yes. Charging below the rated temperature damages the cells.
Yes, before the first full cycle, or it will read as unbalanced under load.