F20 on a Sunsynk ECCO single-phase hybrid SG05LP1: DC side over current fault
Short answer
On a Sunsynk battery, F20 means: DC side over current fault. The battery stops until the fault clears or is reset.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: DC side over current fault.
Part involved: DC side (battery/PV).
When it shows: Hardware DC overcurrent.
Likely causes:
- Overcurrent on battery or from PV; incompatible panels; off-grid start-up with high-power load; damaged components.
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: Turn off DC and AC switches, wait one minute, turn on again; seek help if persists.
What you can check
- Read the full code and message on the inverter screen or in the Sunsynk Connect 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).
- If it happened during a power cut, switch off heavy loads on backed-up circuits before restarting.
- Sunsynk's documented restart: turn off the inverter's DC and AC switches, wait one minute, turn back on - only do this if your installer has shown you the safe shutdown/restart sequence; otherwise ask them.
What the engineer will check
- Check PV and battery connections; check battery C-rating and inverter max discharge current setting; reduce off-grid start loads.
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
- Fault Codes Causes & Solutions Version 1.0 ↗ · Version 1.0 · page 6 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026