Solar · Error codes · Victron Energy
Err21Victron Energy · SmartSolar / BlueSolar MPPT charge controllers
Err21 on a Victron Energy SmartSolar / BlueSolar MPPT charge controllers: Current sensor issue
Short answer
On a Victron Energy inverter, Err21 means: Current sensor issue. The inverter stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Current sensor issue.
Likely causes:
- Current measurement out of range; MPPT minus bypassed.
Is it safe?
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The inverter stops until the fault clears or is reset.
Resetting itself: no - disconnect/reconnect all wires; dealer if persists.
Manual reset: See Victron page.
What you can check
- Read the alarm/error number in the VRM portal or app, or on the GX touch/remote console, and note the time. Check the AC breakers feeding the system are ON. Victron's error pages say diagnosis is for trained professionals - pass the code and a VRM screenshot to your installer.
What the engineer will check
- Disconnect and reconnect all wiring; check PV/battery minus not bypassing controller; replace if persists.
Who to ask for: Victron-trained installer (Victron Professional).
Certification: MCS-certified solar PV installer (MIS 3002) or competent electrician (BS 7671 / Part P in England & Wales); DC work only by PV-trained installer.
What you might notice
Sources
- Victron Energy - MPPT Solar Charger Error Codes (live documentation) ↗ · live page retrieved 2026-09-24 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026