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Fault code index · Solis inverter and battery

Solis Fault Code Index

Every Solis fault code from the inverter display and SolisCloud portal — what it means, the most likely cause, and what to do. Find your code in the index below or use the category sections to browse by system area.
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Very very helpfuland so quick. Made sure that a non expert like myself understood what the problem was and how to resolve it.

Declan S · Jun 2026

Ron is incredibly knowledgeable about solar installs in general but knows givenergy products inside out and the key personnel that worked there from the start to the end. My problem was spurious in its nature but Ron spotted it straight away when he understood the installation details. In essence the installers didn’t fit the correct trip switch. He also gave me hope that in the future hardware repairs could be possible but it’s still early days. This guy really is in the know and keen to sucas a business If you need help don’t hesitate

Geoffrey Heathcote · Jun 2026 Google

STS were incredibly responsive and helpful In diagnosing an issue with my GivEnergy inverter. Although distance meant it was impractical for me to use them to fully solve the issue, I’m grateful for the help and detail they provided. Don is a real professional gent and a hero in my eyes.

Adam Miller · Jun 2026 Google

Thank you for your diligence. On this occasion the battery was able to be saved but they have given a route to hopefully arrange a repair from the manufacturer.

David Bateman · Jun 2026 Google

Massively massively recommended. We had a big battery array (49kW across three phases) put in four years ago. c £35k cost. It’s been a total nightmare for many reasons, not least 1. our installer being totally useless and unresponsive and 2. Givenergy, our battery supplier, going bust. Long story short it had never worked anywhere near properly despite countless hours on phones and emails; the best we’d achieved was one third of the batteries working. Rather than write it off, I asked a PM friend to try to source someone who could come on site and review and revive the system. He found Solar Tech Support and Ron. Ron assured us he was the man to get it going again. After so many years of pain, I was not convinced but, true to his word, five hours later it was up and running. Lovely chap, super knowledgeable with a support team to lean on who are also clearly super technical. I honestly didn’t think there was much chance of getting this array going ever again so was absolutely delighted when Ron and team pulled it off. Bravo!

Will Wynne · Jun 2026 Google

Ron was brilliant. He really tried to help. He spent hours trying to fix our GivEnergy AIO and ultimately it became apparent that it needed parts to fix the BMS management system. As there appears to be no replacement parts available on the market, he gave excellent advice on what options are now available to move forward. He is incredibly helpful and knowledgeable.

Mark Mayson · Jun 2026 Google
How to find your fault code. Solis fault codes appear on the inverter display as an error code string (e.g. "F01", "F05") or in the SolisCloud portal under Device > Event Log. The SolisCloud app also shows the fault history with timestamps. Note the exact code — including any sub-codes shown in parentheses — before contacting support.
Inverter faults

Fault codes generated by the Solis inverter in response to DC voltage issues, temperature, and hardware failures.

F01 / DC over voltagePV voltage too high
PV string voltage exceeds 600V maximum. Do not touch DC cabling. Requires engineer to check string configuration.
F02 / DC insulation fault Insulation fault
Insulation resistance below minimum. Do not touch cabling. Check for water ingress at connectors or cable damage.
F04 / Over temperatureTemperature too high
Inverter over-temperature protection. Check ventilation clearances. Clear vents of dust.
F05 / Relay faultRelay not operating
Inverter relay has not operated correctly. Power cycle. If persistent, relay board may need replacement.
F07 / AFCI arc fault Arc fault
Arc fault detected on DC string. This indicates a dangerous electrical discharge — do not touch DC cabling. Engineer inspection required before restarting.
INI-FAULT / Initialisation faultStartup self-test failed
Inverter failed its startup self-test. Try a full power cycle (AC isolator off, wait 2 minutes, then back on). If the fault persists after a cold start, the control board or firmware may require attention — contact support with the model number and firmware version.
Grid events

Grid voltage and frequency events that cause the inverter to disconnect as a safety protection.

F12 / Grid over voltageOvervoltage disconnect
Grid voltage above upper limit. Contact DNO if recurring.
F13 / Grid under voltageUndervoltage disconnect
Grid voltage below lower limit. Contact DNO if persistent.
F14 / Grid over frequencyOver-frequency disconnect
Grid frequency above limit. Transient, reconnects automatically.
F15 / Grid under frequencyUnder-frequency disconnect
Grid frequency below limit. Transient, reconnects automatically.
F16 / Grid lostNo grid supply
No AC grid supply detected. Check the AC isolator and consumer unit main switch. If supply is confirmed present, check the AC connection to the inverter. The inverter reconnects automatically when grid is restored.
G-IMP / Grid impedance highGrid impedance too high
Grid impedance (resistance of the supply from DNO to property) is above the inverter's threshold. This is a common fault in the UK, particularly on older rural supplies or properties at the end of a long cable run. The inverter disconnects to comply with grid protection requirements. If recurring, contact your DNO to report high impedance on your supply — they can investigate the supply cable.
Isolation / insulation faults

Fault codes related to insulation resistance on the DC and AC sides of the inverter.

F03 / AC isolation fault AC insulation
Insulation fault on the AC side — resistance between AC conductors and earth is below safe minimum. Isolate at consumer unit. Do not touch AC wiring. Requires qualified engineer inspection.
Battery / BMS faults

Fault codes from the battery management system — communication failures and voltage protection events.

F21 / BMS communication failBMS not responding
Inverter has lost RS485 or CAN communication with the battery. Check communication cable, power cycle system. Check firmware compatibility between inverter and battery.
F22 / Battery over voltageVoltage too high
Battery voltage too high. Do not charge further.
F23 / Battery under voltageVoltage too low
Battery deeply discharged. Allow a slow charge recovery cycle.
F24 / Battery over currentCurrent exceeded limit
Charge or discharge current exceeded BMS rating. Requires engineer.
Communication faults

Faults related to data communication between inverter and monitoring portal, and with system components.

Meter comms failMeter offline
Export meter communication failed. Check RS485 cable or CT clamp connections.
SolisCloud offlinePortal not receiving data
Portal not receiving data. Check WiFi stick LED. Reconfigure WiFi if needed via SolisCloud app.
DRM faultDemand response mode
Demand Response Mode fault, typically grid operator demand response signal. Usually clears automatically.
Code not listed here?

Solis releases firmware updates that may introduce new fault codes. If your code isn't listed, share the exact code from your inverter display or SolisCloud and we'll identify it.

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FAQ

Solis fault code questions

Solis fault codes appear on the inverter display as an F-code (e.g. F02, F12). They are also logged in the SolisCloud portal under Device > Event Log, and in the SolisCloud app under fault history. Note the exact F-code number and any sub-code shown in brackets — this helps identify whether the fault is persistent or transient.
F02 is a DC insulation fault — the resistance between the PV string DC conductors and earth has dropped below a safe threshold. This is commonly caused by water ingress at MC4 connectors, damaged string cable insulation, or a faulty panel junction box. Do not touch any DC cabling. Isolate the system at the consumer unit and call a qualified engineer to identify and rectify the fault source before restarting.
Recurring grid faults on Solis RHI models are most commonly caused by grid voltage at the property being consistently above 253V — a common issue in areas with high solar density where solar export is pushing local grid voltage up. Check the voltage reading in SolisCloud or on the inverter display. If voltage is consistently above 250V, contact your DNO — they may need to adjust the local transformer tap or apply a lower export limit.
Yes, persistent Solis fault codes may indicate a hardware fault with the inverter, grid relay, or DC input. STS engineers can review your SolisCloud data remotely from free and advise whether an on-site repair is needed.
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