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Problem diagnosis · Huawei

Huawei FusionSolar Offline — Smart Dongle Reconnection & Monitoring Fix

FusionSolar app or portal showing no data? Your SUN2000 inverter is almost certainly still generating — the Smart Dongle has lost its WiFi connection. This happens after a router change, broadband switch, or WiFi password update. This guide walks through the reconnection process step by step.
  • Smart Dongle WLAN-FE (SDongleA-05)
  • 2.4GHz WiFi only — 5GHz not supported
  • Inverter keeps generating while offline
FusionSolar still dark after trying this guide?

Smart Dongle LED flashing red, FusionSolar not updating after reconnection, or dongle hardware suspected failed? We diagnose remotely in a single session.

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5.0
13 Trustpilot reviews
Trustpilot Google

I have a GivEnergy system consisting of two batteries, two inverters and a controlling EMS (Energy Management System) which has not worked since Nov 2025. After six months I discovered Solar Tech Support, reached out to them and Ron phoned me back – how often do you get that service? Could not be more helpful – worked directly with me over the phone, outside what I would call normal working hours. Lucid explanations and we were able to discuss the issues and history using camera and email history. As this was a very rare setup, Ron was able to access an EMS expert in the field to confirm the solution. One sunny day in, I am now only paying for standing charge and a few pence for spikes in grid consumption while battery catches up with house demand.

Ian · May 2026 Trustpilot

When my GivEnergy system had an issue, I was completely left without support and had honestly lost all hope. Thankfully, I searched online and found Ron, which completely turned things around. After sending him a message, he responded incredibly fast and called me to assure me that he would get the problem fixed. I really admire his dedicated, supportive nature and his determination to find a solution. With this kind of outstanding attitude and customer service, he has absolutely secured a future customer in me.

Sree · May 2026 Trustpilot

Ron want out of is way to help, nothing was to much. He was very thorough in what he did Very knowledgeable I would highly recommend Ron and his company He did a fantastic job for me. if you have any problems, he'll do his best to help you out and resolve your problem. I wouldn't hesitate to recommend them

Dennis Brown · May 2026 Trustpilot

Ron took me through a diagnostic to confirm my GivEnergy Inverter had a fault. A common one as it turns out with the AC Inverter. As GivEnergy is defunct there is no immediate fix, aside from sourcing 2nd hand replacement. It may be that a fix becomes available over the summer which would make a lot of GivEnergy customers happy (Again)

Tony Deacon · May 2026 Trustpilot

Contacted Ron with a problem and he sorted it out quickly with no problems at all. Very knowledgeable on anything solar/ batteries. I would recommend him to anyone

Phill · May 2026 Trustpilot

I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues

michael fairhurst · May 2026 Trustpilot

Contacted Solar Tech Support in desperation. After explaining the issues I had with my system a diagnosis was made and a solution proposed. Fantastic service, even contacted a manufacturer to arrange replacement parts for me. Great communications, explained all they were doing and what I had to do, clearly and precisly. Followed up to confirm all was ok. Excellent service.

Mr Machin · May 2026 Trustpilot

After GivEnergy went into liquidation, just my luck, my battery started playing up (internal board crashed). Contacted my installer - not interested! Found Solar tech support on a Google search. Sooo glad I found this company! Ron is extremely helpful and has plenty of experience. He soon confirmed what the fault was, and helped me to get my system up and running again. Now moved my GivEnergy account to Solar tech support, and will definitely use again if I have more issues. Unusual to find such a helpful company in these times, no morons reading scripts, just direct contact with the engineer.

Keith Ballard · Apr 2026 Trustpilot

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026 Trustpilot

Ron is a super star. Two months ago my GivEnergy battery failed a firmware upgrade leaving it a brick. My installer couldn't/wouldn't fix it. GivEnergy couldn't/wouldn't fix it. Then they went into administration and all hope was lost. A flurry of emails later and Ron had diagnosed the fault (failed USB flash drive, something I'd suspected) and talked me through resolving it. Two months of nothing resolved in about 3 hours. It's great to work with someone who pays attention to the details, knows that they're doing (not just following a script) and gets stuff sorted without a fuss or up-charging.

Christopher · Apr 2026 Trustpilot

I can add to the list of customers who had already 'given up' on GivEnergy due to their appalling customer service, and that was before they went into administration (their Trustpilot reviews don't lie!). So you can imagine my desperation when, having changed my ISP and my Inverter, predictably, proving to be the only device that didn't connect automatically to my new network, I found zero prospect of any customer support with GivEnergy having called in the administrators just five days earlier! The salvation came from Solar Tech Support. My IT advisor stumbled across their web site and some very helpful tips for beleaguered GivEnergy customers, as well as an offer to provide direct assistance. Nothing ventured, I decided to drop them an E-Mail, with very low expectations based on my experience of GivEnergy customer support. Within an hour Ron had responded with some pin point advice, and after a few exchanges of E-Mails he had nailed the problem, enabling the combined efforts of my IT advisor and solar installer to resolve it and reconnect my Inverter. Thank you Solar Tech Support, and Ron in particular, for coming to the aid of a deserted and despondent GivEnergy customer. Expert, razor sharp advice and first class customer service, even though I wasn't officially a customer.

customer · Apr 2026 Trustpilot

This company are a rare gem, I had a very unusual problem following a failed firmware upgrade on my GivEnergy kit. I then found out GivEnergy were in administration and had dismissed all their support staff! None of the usual fixes to try and restore my inverter comms would work, and I looked everywhere, forums, GivEnergy youtube support videos - even AI couldn't figure it out. My installer was talking about huge sums for system replacements, and being vague / evasive about if they'd even install replacement GivEnergy inverter. Enter Solar Tech Support, reassuring and knowledgeable from the very start, I've learnt loads about my solar system though the friendly chat while my engineer worked as he diagnosed the problem and figured out a fix procedure that I've not found anywhere else - amazing . If you need solar system repairs - especially if you like me have been left high and dry by GivEnergy, I cannot recommend this company enough. Give them a call.

Andy Thomas · Apr 2026 Trustpilot

I sent a message on their website regarding a problem I have on my Givenergy system. Although not supplied by Ronald, I thought it was worth an email. Within the hour on a Saturday, he phoned and we discussed the problem. He logged in remotely and gave excellent advice. I'm too far away for his on-site help but he did diagnose the problem and was happy also to chat through my thoughts about an upcoming solar/battery install I'm planning. Great bloke.... if only he was nearer!

Philip · Apr 2026 Trustpilot

I have a GivEnergy system consisting of two batteries, two inverters and a controlling EMS (Energy Management System) which has not worked since Nov 2025. After six months I discovered Solar Tech Support, reached out to them and Ron phoned me back – how often do you get that service? Could not be more helpful – worked directly with me over the phone, outside what I would call normal working hours. Lucid explanations and we were able to discuss the issues and history using camera and email history. As this was a very rare setup, Ron was able to access an EMS expert in the field to confirm the solution. One sunny day in, I am now only paying for standing charge and a few pence for spikes in grid consumption while battery catches up with house demand.

Ian · May 2026 Trustpilot

When my GivEnergy system had an issue, I was completely left without support and had honestly lost all hope. Thankfully, I searched online and found Ron, which completely turned things around. After sending him a message, he responded incredibly fast and called me to assure me that he would get the problem fixed. I really admire his dedicated, supportive nature and his determination to find a solution. With this kind of outstanding attitude and customer service, he has absolutely secured a future customer in me.

Sree · May 2026 Trustpilot

Ron want out of is way to help, nothing was to much. He was very thorough in what he did Very knowledgeable I would highly recommend Ron and his company He did a fantastic job for me. if you have any problems, he'll do his best to help you out and resolve your problem. I wouldn't hesitate to recommend them

Dennis Brown · May 2026 Trustpilot

Ron took me through a diagnostic to confirm my GivEnergy Inverter had a fault. A common one as it turns out with the AC Inverter. As GivEnergy is defunct there is no immediate fix, aside from sourcing 2nd hand replacement. It may be that a fix becomes available over the summer which would make a lot of GivEnergy customers happy (Again)

Tony Deacon · May 2026 Trustpilot

Contacted Ron with a problem and he sorted it out quickly with no problems at all. Very knowledgeable on anything solar/ batteries. I would recommend him to anyone

Phill · May 2026 Trustpilot

I've spoken to Ron a couple of times with issues with my Givenergy installation. Such a friendly knowledge guy very highly recommended. Thank you very much for resolving my issues

michael fairhurst · May 2026 Trustpilot

Contacted Solar Tech Support in desperation. After explaining the issues I had with my system a diagnosis was made and a solution proposed. Fantastic service, even contacted a manufacturer to arrange replacement parts for me. Great communications, explained all they were doing and what I had to do, clearly and precisly. Followed up to confirm all was ok. Excellent service.

Mr Machin · May 2026 Trustpilot

After GivEnergy went into liquidation, just my luck, my battery started playing up (internal board crashed). Contacted my installer - not interested! Found Solar tech support on a Google search. Sooo glad I found this company! Ron is extremely helpful and has plenty of experience. He soon confirmed what the fault was, and helped me to get my system up and running again. Now moved my GivEnergy account to Solar tech support, and will definitely use again if I have more issues. Unusual to find such a helpful company in these times, no morons reading scripts, just direct contact with the engineer.

Keith Ballard · Apr 2026 Trustpilot

Contacted Solar Tech Support when trying to understand what my Givenergy inverter problem might be and what might be my options. Received good/honest advise which backed up my thoughts.

Hugh Speirs · Apr 2026 Trustpilot

Ron is a super star. Two months ago my GivEnergy battery failed a firmware upgrade leaving it a brick. My installer couldn't/wouldn't fix it. GivEnergy couldn't/wouldn't fix it. Then they went into administration and all hope was lost. A flurry of emails later and Ron had diagnosed the fault (failed USB flash drive, something I'd suspected) and talked me through resolving it. Two months of nothing resolved in about 3 hours. It's great to work with someone who pays attention to the details, knows that they're doing (not just following a script) and gets stuff sorted without a fuss or up-charging.

Christopher · Apr 2026 Trustpilot

I can add to the list of customers who had already 'given up' on GivEnergy due to their appalling customer service, and that was before they went into administration (their Trustpilot reviews don't lie!). So you can imagine my desperation when, having changed my ISP and my Inverter, predictably, proving to be the only device that didn't connect automatically to my new network, I found zero prospect of any customer support with GivEnergy having called in the administrators just five days earlier! The salvation came from Solar Tech Support. My IT advisor stumbled across their web site and some very helpful tips for beleaguered GivEnergy customers, as well as an offer to provide direct assistance. Nothing ventured, I decided to drop them an E-Mail, with very low expectations based on my experience of GivEnergy customer support. Within an hour Ron had responded with some pin point advice, and after a few exchanges of E-Mails he had nailed the problem, enabling the combined efforts of my IT advisor and solar installer to resolve it and reconnect my Inverter. Thank you Solar Tech Support, and Ron in particular, for coming to the aid of a deserted and despondent GivEnergy customer. Expert, razor sharp advice and first class customer service, even though I wasn't officially a customer.

customer · Apr 2026 Trustpilot

This company are a rare gem, I had a very unusual problem following a failed firmware upgrade on my GivEnergy kit. I then found out GivEnergy were in administration and had dismissed all their support staff! None of the usual fixes to try and restore my inverter comms would work, and I looked everywhere, forums, GivEnergy youtube support videos - even AI couldn't figure it out. My installer was talking about huge sums for system replacements, and being vague / evasive about if they'd even install replacement GivEnergy inverter. Enter Solar Tech Support, reassuring and knowledgeable from the very start, I've learnt loads about my solar system though the friendly chat while my engineer worked as he diagnosed the problem and figured out a fix procedure that I've not found anywhere else - amazing . If you need solar system repairs - especially if you like me have been left high and dry by GivEnergy, I cannot recommend this company enough. Give them a call.

Andy Thomas · Apr 2026 Trustpilot

I sent a message on their website regarding a problem I have on my Givenergy system. Although not supplied by Ronald, I thought it was worth an email. Within the hour on a Saturday, he phoned and we discussed the problem. He logged in remotely and gave excellent advice. I'm too far away for his on-site help but he did diagnose the problem and was happy also to chat through my thoughts about an upcoming solar/battery install I'm planning. Great bloke.... if only he was nearer!

Philip · Apr 2026 Trustpilot
ℹ️

Your inverter is still generating. FusionSolar going offline means the monitoring link is broken, not the system itself. The SUN2000 inverter and LUNA2000 battery (if fitted) continue operating normally. What you lose is visibility — you cannot see generation data, battery status, or fault alerts until the Smart Dongle reconnects.

Diagnostics

6-step FusionSolar reconnection guide

Start with a power cycle (step 3). If that doesn't work, reconnect the WiFi (step 4). If WiFi is unreliable at the inverter location, skip to the Ethernet fallback (step 6).

1

Confirm the inverter is still generating

Check the LED display on the front of the SUN2000 inverter. If it shows generation figures (watts or kilowatts), the inverter is running normally — the offline issue is purely a monitoring connectivity problem.

Display showing generation

Inverter is fine. Problem is the Smart Dongle connection to FusionSolar. Continue to step 2.

Display blank or showing fault

Inverter has a separate issue. Check for fault codes and see our AFCI fault or inverter not turning on guides.

2

Check the Smart Dongle LED indicator

The Smart Dongle (model SDongleA-05, also called the WLAN-FE) is a small module plugged into the USB port on the bottom of the SUN2000 inverter. Check its LED:

Solid green: Connected to WiFi and communicating with FusionSolar. If FusionSolar still shows no data, the issue may be cloud-side or account-related — not the dongle.
Flashing green: Powered but trying to connect. WiFi credentials have changed or signal is too weak. Needs reconfiguring (step 4).
Red or off: Connection failure or hardware fault. Try a power cycle first (step 3). If still red/off, the dongle may need replacing.

If the dongle is not physically present, it may have been removed or never installed. The inverter will generate without a dongle but cannot send data to FusionSolar.

3

Power cycle the inverter and Smart Dongle

A power cycle clears temporary communication faults and forces the dongle to re-establish its connection. Follow this exact sequence:

1. Turn off the AC isolator (the switch on your consumer unit or next to the inverter)
2. Turn off the DC isolator (the rotary switch on the bottom of the inverter)
3. Wait 60 seconds — this allows capacitors to discharge fully
4. Turn the DC isolator back on
5. Turn the AC isolator back on

Wait 5 minutes, then check FusionSolar. If data reappears, the issue was a temporary communication fault.

Still offline? The dongle needs its WiFi credentials reconfigured. Move to step 4.
4

Reconnect the Smart Dongle WiFi via the FusionSolar app

You need to be physically near the inverter for this step. The FusionSolar app connects directly to the dongle's local WiFi network to reconfigure it.

1. Open the FusionSolar app on your phone (iOS or Android).
2. Tap "Me" (bottom right) → then "Device commissioning".
3. Scan the QR code on the right side of the inverter — this connects your phone to the dongle's WiFi network.
4. Log in with the installer account — default password is 00000a. If this has been changed by your installer, you will need their credentials or a reset.
5. Navigate to Settings → Communication configuration → Router connection settings.
6. Select your home WiFi network (must be 2.4GHz — the dongle does not support 5GHz). Enter the password. Tick "Keep Trying Wi-Fi" and tap Connect.

The dongle supports 802.11b/g/n on 2.4GHz only (2.412–2.484 GHz). If your router uses a combined 2.4/5GHz network, the dongle may fail to connect. Create a separate 2.4GHz SSID or disable band steering.

5

Enable the management system connection

After reconnecting WiFi, stay in the Communication configuration screen:

1. Select "Management system settings"
2. Enable the authorization checkbox
3. Enable TLS encryption
4. Tap Connect

This re-establishes the secure link between the Smart Dongle and the FusionSolar cloud. Wait 5–10 minutes, then check FusionSolar for live data. The dongle LED should turn solid green.

Data from the period the dongle was offline will be missing. If the inverter stored data locally during the outage, some historical data may backfill automatically — but this depends on the inverter model and firmware version.

6

If WiFi keeps failing — use an Ethernet cable instead

The Smart Dongle WLAN-FE has a 10/100M Ethernet (RJ45) port as well as WiFi. If WiFi is unreliable at the inverter location — common in garages, lofts, or buildings with thick walls — Ethernet provides a permanent, stable alternative.

• Run a Cat5e or Cat6 Ethernet cable from the dongle's RJ45 port to your router (or a network switch)
• The dongle will detect the wired connection automatically
• WiFi can be disabled once Ethernet is confirmed working
• Connection should register on FusionSolar within 5 minutes

If running a cable to the router is impractical, a powerline adapter pair (e.g. TP-Link AV600) can bridge the gap using your home's mains wiring.

Why FusionSolar goes offline — and why it matters

Huawei SUN2000 inverters use a Smart Dongle (SDongleA-05 WLAN-FE) to send generation, battery, and fault data to the FusionSolar cloud platform. The dongle connects to your home WiFi on the 2.4GHz band and maintains a persistent encrypted link to Huawei's servers. When you change your broadband provider, get a new router, or update your WiFi password, the stored credentials in the dongle no longer match and the connection drops. This is the single most common reason FusionSolar goes dark.

While the monitoring link is down, the inverter and battery continue operating normally — you do not lose any generation or storage capability. What you lose is visibility: you cannot see how much the system is generating, whether the battery is charging and discharging correctly, or whether any fault conditions have occurred. For homeowners on the Smart Export Guarantee (SEG) or time-of-use tariffs, monitoring data is also useful for verifying that battery dispatch and export schedules are working as configured.

If the steps above do not resolve the issue, the Smart Dongle hardware itself may have failed. Dongle failures are relatively uncommon but do occur, particularly after power surges or firmware update failures. STS can confirm whether the dongle needs replacing based on LED behaviour and FusionSolar account status. Replacement dongles are available from Huawei solar distributors in the UK.

FAQ

FusionSolar offline — common questions

The most common cause is the Smart Dongle losing its WiFi connection after a router change, broadband switch, or WiFi password update. The dongle stores your WiFi credentials internally and cannot reconnect when they change. Less common causes include dongle hardware failure, a firmware update that disrupted connectivity, or a FusionSolar cloud outage. Your inverter continues generating normally while FusionSolar is offline.
Open the FusionSolar app, tap Me → Device commissioning. Scan the QR code on the inverter to connect to the dongle's local WiFi. Log in with the installer account (default password: 00000a). Go to Settings → Communication configuration → Router connection settings. Select your 2.4GHz home WiFi network and enter the password. See step 4 above for the full walkthrough.
Solid green means connected and communicating with FusionSolar. Flashing green means powered but trying to connect — the WiFi credentials need reconfiguring. Red or off means a connection failure or possible hardware fault. If the LED is off entirely, check the dongle is firmly seated in the inverter's USB port and try a power cycle.
Yes. The Smart Dongle WLAN-FE has a 10/100M Ethernet (RJ45) port. Run a Cat5e or Cat6 cable from the dongle to your router for a permanent, stable connection. This is the recommended approach if WiFi is unreliable at the inverter location — particularly in garages, lofts, or buildings with thick walls. A powerline adapter pair can bridge the gap if running a cable directly is impractical.
Repeated disconnections are usually caused by weak WiFi signal at the inverter, router band steering forcing the dongle onto 5GHz (which it doesn't support), or router firmware dropping idle connections. Try creating a dedicated 2.4GHz network, moving the router closer, or switching to an Ethernet cable connection. A dongle firmware update may also help — check via the FusionSolar app.
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FusionSolar still offline after trying this guide?

Smart Dongle LED still red, FusionSolar not updating, or dongle hardware suspected failed? We diagnose Huawei monitoring issues remotely using your FusionSolar account data and dongle status. Most issues resolved in a single session.

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