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Battery fault · All brands

Battery communication fault

Your inverter is reporting that it cannot communicate with the battery — a CAN bus fault, BMS error, or battery not seen on the communication bus. This disables battery operation as a safety measure.
  • Battery hardware is often fine
  • Firmware mismatch is a common cause
  • Do not open battery enclosure
Communication faults often need firmware work

Firmware mismatches and BMS resets usually require remote or on-site engineer access. A diagnostic session identifies the exact cause and the correct fix route.

Book your free remote diagnosticSystem repair service

Safety: do not open battery or inverter enclosures. Internal DC voltage is dangerous even with AC supply isolated.

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

What is a CAN communication fault?

CAN (Controller Area Network) is the communication protocol that most solar battery systems use to allow the inverter and battery to talk to each other. Over this link the inverter sends charge and discharge commands; the battery returns state of charge, voltage, temperature, and cell health data.

When this communication path breaks down, the inverter cannot safely control the battery. As a protection measure, it disables battery operation entirely and raises a communication fault alarm.

The break can be in the physical cable, the communication ports on either device, the protocol version (caused by firmware mismatches), or a locked BMS that isn't responding to communication attempts.

Do not open your battery or inverter enclosures. Battery packs contain high-voltage DC — typically 48V to 400V depending on system type. This voltage is present even when the AC supply is isolated. There are no user-serviceable components inside. All physical inspection of internal components must be carried out by a qualified engineer.

Common causes

Listed from most to least commonly encountered.

Firmware version mismatch

Inverter and battery firmware updated to incompatible versions — typically after a cloud-pushed update that updates one side but not the other. The CAN protocol versions no longer align.

Loose or damaged communication cable

The BMS cable between inverter and battery is not fully seated, has been pulled under tension, or the RJ45 clip has broken. Causes intermittent or persistent communication loss.

BMS protection lock

The battery BMS has entered a protection state — from over-discharge, cell imbalance, over-temperature, or a hard fault — and is not responding to communication attempts.

Incorrect BMS protocol setting

Many inverters require the BMS communication protocol to be manually set to match the battery brand (e.g. Pylon, BYD, GivEnergy, custom). An incorrect protocol setting means the two devices transmit on different 'dialects' and cannot understand each other.

Communication port hardware fault

Less common. The CAN communication port on the inverter or battery has failed — from power surge, physical damage, or hardware defect. Requires component replacement.

CAN bus termination issue

In multi-battery systems, the CAN bus requires correct termination resistors at each end of the daisy chain. Missing or incorrect termination causes communication instability across all batteries in the stack.

What you can check safely

These are the checks you can make without opening any enclosures.

1
Note the exact fault code

Open the event log in your monitoring portal and record the exact fault code and the time it first appeared. Different codes indicate different parts of the communication path. For GivEnergy faults, see the GivEnergy fault codes guide. The code and timing are the most useful information you can bring to a diagnostic session.

2
Check when the fault first appeared

Look at the event log timeline. Did the fault appear immediately after a firmware update notification? After a power cut? After a particularly cold or hot period? The timing often points directly at the cause — firmware mismatch, protection trip, or environmental trigger.

3
Check the external communication cable

Without opening any enclosures, look at the communication cable between the inverter and battery — typically an RJ45 cable going into a BMS or CAN port on the side or bottom of each unit. Check it is firmly plugged in at both ends and hasn't been disturbed. A partially seated connector can cause persistent faults.

4
Perform a controlled power cycle

Turn off the inverter via its AC and DC isolation switches. Turn off the battery using its own shutdown button or circuit breaker. Wait 2 full minutes. Turn the battery on first, wait 30 seconds, then turn the inverter back on. Allow 5 minutes for the communication to re-establish. Check whether the fault has cleared in the portal.

5
Check the battery's own status lights

Look at the battery unit itself for status LED indicators. A red or amber light on the battery (separate from the inverter) suggests the battery BMS has its own fault or is in a protection state. Note what colour and pattern of lights you see — this informs whether the battery needs a BMS reset rather than a communication cable fix.

FAQ

Frequently asked questions

The inverter can no longer communicate with the battery's BMS over the CAN bus or RS485 link. The battery hardware may be fine — the fault is in the communication path between the two devices. The inverter disables battery operation as a protection measure until communication is restored.
The inverter's response — disabling battery operation — is a protection measure. The system should continue generating to the grid or house loads. Do not attempt to open battery or inverter enclosures. If you see physical damage, smell burning, or the battery feels hot, isolate the system and call an engineer immediately.
Yes — this is one of the most common causes. An over-the-air update that updates the inverter but not the battery can cause protocol incompatibility. Resolving this requires updating the battery firmware to the compatible version, which typically needs engineer access.
Intermittent faults are usually caused by a loose communication cable connector, a connector that is partially seated, or a faulty port. Temperature cycling can cause connectors to expand and contract, making faults appear at certain times of day. Check all external cable connections are firmly seated.
The safe self-help steps are: recording the fault code, checking external cable connections, and performing a controlled power cycle. Firmware updates, BMS resets, and internal component inspection require qualified engineer access. Do not open battery or inverter enclosures.
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Need help diagnosing this fault?

Communication faults are one of the more complex fault types — the exact cause determines whether it is a cable fix, a firmware update, or a hardware replacement. A remote diagnostic session reviews your event log, firmware versions, and fault history to give you a clear answer.

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