JK BMS Settings for LiFePO4: 8S and 16S, 280Ah and 314Ah
Good JK BMS settings for LiFePO4 are a set of per-cell values, not a single magic number. For EVE or CATL 280Ah and 314Ah cells, charge to about 3.45 to 3.60 V per cell, cut off discharge at about 2.5 to 2.95 V, and start balancing near 3.40 V. The same per-cell values work for 8S (24 V) and 16S (48 V) packs. Only the pack totals change.
How the per-cell values become pack voltage
The JK BMS asks for voltages per cell. Pack voltage is cells times the per-cell value. For a 16S pack, a Cell OVP of 3.60 V means 57.6 V at the pack. For an 8S pack, the same setting means 28.8 V.
You do not need separate "8S settings" and "16S settings". Enter the same per-cell numbers and set the cell count in the BMS. A 48 V pack is 16S LiFePO4 (nominal 51.2 V). A 24 V pack is 8S (nominal 25.6 V).
Gentle, medium or hard
The three levels trade usable capacity against cycle life. LiFePO4 wears faster when it sits at high voltage, is charged hard, or is cycled near empty.
- Hard: close to the cell datasheet limits with a small margin. Most usable capacity, shortest life.
- Medium: a softer everyday window. A good default for most home storage.
- Gentle: stays away from both ends and uses lower currents. Less capacity per cycle, longest life.
LiFePO4 has a very flat voltage curve. Most of the energy sits between about 3.0 and 3.4 V, so giving up the last few percent at the top and bottom costs little capacity.
Recommended JK BMS settings for LiFePO4 per cell
Ranges come from the editor's LiFePO4 recommendations (EVE LF280K datasheet, Gobel Power, JK manuals and community sources). The three levels are the editor presets. All values are per cell.
| Parameter | Range | Hard | Medium | Gentle |
|---|---|---|---|---|
| Cell OVP | 3.55 to 3.65 V | 3.65 V | 3.60 V | 3.55 V |
| Cell OVP recovery | 3.35 to 3.55 V | 3.45 V | 3.40 V | 3.35 V |
| Cell RCV (request charge voltage) | 3.45 to 3.55 V | 3.55 V | 3.50 V | 3.45 V |
| Cell RFV (request float voltage) | 3.35 to 3.40 V | 3.40 V | 3.37 V | 3.35 V |
| SOC-100% voltage | 3.41 to 3.55 V | 3.50 V | 3.45 V | 3.41 V |
| Cell UVP | 2.50 to 2.95 V | 2.50 V | 2.80 V | 2.95 V |
| Cell UVP recovery | 2.65 to 3.10 V | 2.70 V | 3.00 V | 3.10 V |
| SOC-0% voltage | 2.60 to 3.05 V | 2.60 V | 2.90 V | 3.05 V |
| Start balance voltage | 3.40 to 3.45 V | 3.40 V | 3.40 V | 3.40 V |
| Balance trigger voltage | 0.005 to 0.010 V | 0.010 V | 0.010 V | 0.005 V |
| Charge OTP | 45 to 60 °C | 55 °C | 50 °C | 45 °C |
| Discharge OTP | 50 to 60 °C | 60 °C | 55 °C | 50 °C |
| Charge UTP | 0 to 10 °C | 2 °C | 5 °C | 10 °C |
| Discharge UTP | -20 to -10 °C | -20 °C | -15 °C | -10 °C |
The presets also set the recovery temperatures and the power-off voltage. Open the editor to see them next to your own file.
Charge and discharge currents
The presets set currents as a C-rate times the pack capacity, capped by the BMS rating. A JK model ending in 20P, such as the PB2A16S20P, is rated 200 A.
| Level | Charge, discharge (C) | 280Ah pack | 314Ah pack |
|---|---|---|---|
| Hard | 1.0 C, 1.0 C | 200 A, 200 A | 200 A, 200 A |
| Medium | 0.5 C, 0.7 C | 140 A, 196 A | 157 A, 200 A |
| Gentle | 0.3 C, 0.5 C | 84 A, 140 A | 94 A, 157 A |
On a 200 A BMS, the BMS rating is the limit at the hard level. For solar storage, gentle charge current is usually plenty.
Keep the order chains valid
The voltages must follow strict order. Equal values are rejected too.
- Cell OVP recovery, then SOC-100% voltage, then Cell RCV, each strictly higher than the one before.
- Cell UVP, then SOC-0% voltage, then Cell UVP recovery, each strictly higher than the one before.
If a chain is broken, the JK app refuses the import with "This parameter does not apply to the connected device. (Sending failure)". See JK BMS Sending failure for the full list of causes. The editor checks these rules while you edit, and when you write over Bluetooth it also sends the changes in an order that never crosses a chain.
Common mistakes
Is 3.65 V per cell a good Cell OVP for LiFePO4?
It is the top of the range and the hard level. It is a protection limit, not a target. Charge with a lower RCV and let OVP act only as a safety net.
Do I need different settings for 280Ah and 314Ah cells?
No. The voltages are the same. Only the current limits and the capacity setting change.
Why does my file fail even though the final values look valid?
The JK app writes settings one at a time and checks each against the values the BMS holds at that moment. The editor can split your edits into steps that are safe in any order, or write them over Bluetooth in that order for you.
For more detail on each field, see JK BMS parameters explained and JK BMS balance settings. To fix SOC drift after changing the SOC voltages, read JK BMS SOC calibration. Other chemistries are covered in JK BMS NMC and LTO settings.
Next step
After you apply the values, check the log for OVP cycling or UVP trips. Load a Detail Log on the log analysis page and look for repeated protection events. Read why cell overcharge protection keeps tripping for the charge side, and finding a weak cell in the log when one cell is behind the rest.
Browse the ready values on the presets page, then connect your BMS or open your .jkcfg in the editor to apply a level, check it and write it back.
Related guides
- JK BMS Parameters Explained: Every Setting by GroupJK BMS parameters explained in one glossary: cell OVP, OVPR, UVP, UVPR, balance, SOC, RCV and RFV, current and temperature limits, with typical LFP ranges.
- JK BMS Settings for NMC and LTO: Safe Per-Cell ValuesJK BMS settings for NMC and LTO packs: per-cell OVP, UVP, balance, temperature and C-rate values in three wear levels, plus how the editor detects chemistry.
- JK BMS Cell Over Charge Protection Keeps Tripping: Causes and FixJK BMS cell over charge protection tripping and releasing every minute? See why a charger set too high causes it, how to tell it from a weak cell, and how to fix it.