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Huawei · Common problems & faults

Huawei common problems & faults

STS engineers diagnose and repair 6 common problems & faults on Huawei systems. Click any topic below for a full step-by-step guide, or book a free remote diagnostic and we'll tell you what the fix is. The WiFi is the exception: it's never remote work. If the WiFi still won't connect after the guide, we can set it up on site, from £195.
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Sts does a extremely great job. Thank you.

Roy Morgan · Jul 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

Ron very quickly diagnosed what was wrong with my GivEnergy system. Unfortunately the kit has died after only 3.5 years of use-which is quite sad and timing couldn’t be worse with GivEnergy gone bust. Ron gave me advise on how to handle this with my installer. I’m hoping they’ll be forthcoming, but if they aren’t i now have a good idea how to deal with that. Thanks a lot Ron!

Dennis Koenen · Jul 2026 Google

Great service from STS after a power cut and brownout left my GivEnergy inverters effectively useless. After filling the enquiry form out I was promptly given clear instructions by email explaining how to run their diagnostic software and they were working remotely in minutes. Soon after my inverters were back running again. Very helpful and knowledgeable people - thank you.

Dan · Oct 2026 Google

My old solax packed in and was replaced by solar tech support. I am impressed at the very short time scale, sorted in only 3 days. Some were quoting 2-3 weeks. The old unit and all the packing was taken away.

Paul Riddick · Jul 2026 Google

Great experience with STS great communication from Ron, very helpful and knowledgable. Installed me a second Givenergy battery to help take the strain off my original 9.5 that needs refurb due to a weak cell. They secured me an 8.2 arranged install. Levi arrived the whole install was done within 1.5 hours - great tidy job. Worked with me to alter my setup to allow easy removal of my 9.5 when i can get it away for refurb - very happy with their service and its reassuring to know there is a company out there that can help look after my givenergy system

Alan Glaister · Sep 2026 Google

Written by · Independent Solar Engineer Last updated

What actually goes wrong with Huawei kit

Most Huawei problems we see are not the inverter itself. The SUN2000 is reliable hardware; what fails is the kit around it and the settings behind it. The single most common call is FusionSolar going offline because the Smart Dongle has lost its WiFi after a router change. The system usually keeps running, but offline doesn't prove it, so check the inverter's own screen or status lights. Until the dongle is reconnected, you are flying blind. Our Smart Dongle WiFi guide takes you through reconnecting it. If it still won't connect, we set it up on site, from £195: we connect it to your WiFi, set up your router, including a separate 2.4 GHz network if it needs one, and check it's reporting.

After comms it is configuration. A LUNA2000 battery that never charges usually has the FusionSolar working mode set to Fully Fed to Grid. Backup that did nothing in a power cut normally means there is no Backup Box fitted or off-grid mode was never enabled. Low yield often traces back to an export limit or a CT clamp reading wrong, and many of these settings sit behind installer-level FusionSolar access.

Because nearly all of this shows up in FusionSolar data, we diagnose remotely first: alarm log, string voltages, working modes. Settings faults are fixed in a single session. Genuine hardware faults, like a repeating AFCI arc alarm, get narrowed to a likely string before anyone climbs a ladder.

Common problems & faults

6 common problems & faults we cover

Each topic links through to an engineer-led step-by-step guide.

FusionSolar offline? Reconnect the Smart Dongle

Huawei FusionSolar offline or showing a network connection error? It's usually the Smart Dongle WiFi, not the inverter.

See FusionSolar offline

LUNA2000 battery not charging — causes and fix

Huawei LUNA2000 stuck at the same SOC? Usually FusionSolar working mode is on Fully Fed to Grid — plus BMS faults, charge schedules and…

See LUNA2000 battery not charging

Smart Dongle / Smart Logger WiFi not connecting

Huawei Smart Dongle or Smart Logger won't connect to WiFi or FusionSolar? Find the device hotspot, reset it, set a 2.4GHz router, and check…

See details

SPS Backup Not Working — Backup Box and Off-Grid

Huawei battery did not kick in during a power cut? SPS backup needs a Backup Box, off-grid mode enabled in FusionSolar, and an SOC reserve.

See SPS Backup Not Working

SUN2000 AFCI fault (DC arc) — how to clear it

Huawei SUN2000 AFCI alarm? It's detected a DC arc fault. A single trip is often a nuisance; repeated trips mean a real wiring fault to find…

See SUN2000 AFCI fault (DC arc)

SUN2000 Underperforming — Low Generation

Huawei SUN2000 generating less than expected? Usually export limiting, shading, a dead string/MPPT, inverter derating or panel soiling — how…

See SUN2000 Underperforming
FAQ

Huawei fault questions answered

The usual culprit is the Smart Dongle losing its WiFi, typically after a router change, broadband switch or new WiFi password. The dongle only supports 2.4GHz, so mesh routers with band steering knock it off too. In most cases only the monitoring is down: the system usually keeps running, so check the inverter's own screen or status lights. Then look at the dongle LED: solid green means connected, flashing green means it needs reconnecting through the FusionSolar app, or wire it to your router by Ethernet for a permanent fix.
Most of them, yes. The bulk of Huawei problems are settings: working modes, charge schedules, export limits and backup configuration, all of which we can sort through FusionSolar with installer-level access. The exception is a Smart Dongle that still won't reconnect to your WiFi after the steps in our Smart Dongle WiFi guide: WiFi isn't remote work, so we can set it up on site, from £195. Physical faults are the other exception: an AFCI arc alarm, a dead string or a failed optimiser needs an engineer on site, but the remote work narrows the fault down first so the visit goes straight to the right spot.
The remote diagnostic is free. We read your FusionSolar data, tell you what is wrong and what fixing it involves, and that costs nothing whatever the outcome. If it is something we can put right remotely, such as a working mode, the fix is £125 on a no fix, no fee basis. A Smart Dongle that won't reconnect to your WiFi is on-site work, from £195, and anything else that genuinely needs an engineer on site is quoted before we book it.
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Tell us what's happening with your Huawei system. Free remote diagnostic, no-fix-no-fee. Most configuration faults resolved during the 30-minute session. We don't set up or diagnose WiFi remotely or over the phone: it's quicker and more reliable done on site.

  • No fix, no fee covers remote fixes. On-site work is quoted in writing before we start.
  • Emergency response within 4 hours during business hours
  • Written report regardless of outcome

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