F56 on a Zhejiang Deye Electrical Appliances Co., Ltd. Deye SUN-SG04LP1-EU single-phase hybrid: Battery voltage low
Short answer
On a Zhejiang Deye Electrical Appliances Co., Ltd. battery, F56 means: Battery voltage low. The battery stops until the fault clears or is reset.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Battery voltage low.
Part involved: battery/DC bus.
Likely causes:
- Battery voltage too low.
Is it safe?
| Does the battery stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
The battery stops until the fault clears or is reset.
Resetting itself: yes.
Manual reset: Charge battery using PV or grid.
What you can check
- Read the full code and message on the inverter screen or in the Deye Cloud / installer app and note the date/time for your installer.
- Check the inverter's AC isolator next to the inverter and the solar/battery breaker in the consumer unit are ON (do not reset a breaker that trips again - call your installer).
- Check battery SoC in the app.
What the engineer will check
- Check battery voltage/BMS and discharge limits.
Who to ask for: Battery/hybrid installer trained on the specific battery (manufacturer-approved installer).
Certification: Battery and hybrid-inverter DC work: installer trained/approved by the manufacturer; electrical work under BS 7671 by a competent person.
What you might notice
Sources
- Hybrid Inverter User Manual SUN-3K/3.6K/5K/6K-SG04LP1-EU ↗ · Deye Hybrid Inverter User Manual SUN-3K/3.6K/5K/6K-SG04LP1-EU (file dated 2026-04-27) · page 47 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026