SUN-5-12K-SG01HP3-EU-DM2 three-phase hybrid (F-series table)
Deye F51 error code
Battery temperature reported by the BMS is too high.
Likely causes
- Battery over-temperature
- Poor ventilation or high ambient temperature
- BMS temperature-sensor fault
- High charge or discharge current
Checks to run, in order
- 1Check the BMS temperature reading
- 2Check the battery-room ventilation
- 3Check the charge and discharge current
- 4Check BMS communication
Fixes
- Ventilate and cool the battery room
- Reduce the charge or discharge current
- Restart after the battery has cooled
When to escalate
If the BMS temperature reads normal and F51 persists, the distributor should check BMS communication and parameters.
Fix it with the right tools
Check the system around the fault before replacing parts: load, battery bank, PV string and commissioning settings. If you need a second opinion, send the code and your inverter model to our team.
Before you open the inverter
- Isolate both the AC and DC sides, then confirm the display is dead before touching terminals.
- Use insulated tools and one hand where possible. DC arcs do not self-extinguish like AC.
- If you see burnt terminals, swollen cells, leaking electrolyte or a burning smell, stop and escalate instead of resetting the fault.
Questions installers ask
What does Deye F51 mean?
Battery temperature reported by the BMS is too high.
How do I fix Deye F51?
Ventilate and cool the battery room Reduce the charge or discharge current Restart after the battery has cooled
When should I escalate Deye F51?
If the BMS temperature reads normal and F51 persists, the distributor should check BMS communication and parameters.
Can I reset Deye F51 myself?
Only after isolating the AC and DC sides and running the checks above. If Deye F51 returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show Deye F51?
Deye F51 is documented for SUN-5-12K-SG01HP3-EU-DM2 three-phase hybrid (F-series table). Confirm the code on your own unit's display or manual before ordering parts.
More Deye error codes
- Deye F01PV input polarity is reversed at one or both DC inputs.
- Deye F02PV insulation resistance to earth is below the safety limit.
- Deye F03Ground fault detected on the PV array (GFDI).
- Deye F04GFDI ground-failure alarm: the PV array or inverter is not properly earthed.
- Deye F05Control-board EEPROM read failure.
- Deye F06Control-board EEPROM write failure.
Guidance reviewed 17 October 2026 by the Mishka Energy installer team. Error codes vary by brand, model family and firmware; confirm against the manufacturer manual.
Back to troubleshooting