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Problem diagnosis · SolaX Power

SolaX BMS Communication Fault — T-BAT & Triple Power Fix

Your SolaX inverter has lost communication with the T-BAT or Triple Power battery. The battery may show 0% state of charge, the inverter will not charge or discharge, and SolaX Cloud is reporting a BMS fault. The most common causes are a loose CAN bus cable, the wrong battery type selected in the inverter, or a DIP switch error on stacked modules.
  • Not affiliated with SolaX Power
  • Free remote diagnostic · no fix, no fee
  • All T-BAT & Triple Power models
Battery showing 0% or BMS fault?

A BMS communication fault means the inverter cannot read the battery. The battery itself is usually fine — the communication path needs fixing. We diagnose remotely via SolaX Cloud fault logs and guide the resolution.

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Independent — not affiliated with SolaX Power.

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
Quick reference — SolaX BMS fault codes
BMS_Lost — Inverter cannot detect battery at all
BMS_Internal_Err — DIP switch or loose CAN cable
C1 / CAN1 Fault — General CAN bus communication error
BMS Relay Fault — BMS control board failure
Diagnostics

6-step BMS fault diagnosis

Work through these steps to identify why the inverter has lost communication with your T-BAT or Triple Power battery. Start with the simplest checks before moving to configuration.

1

Check SolaX Cloud for BMS fault codes

Log into SolaX Cloud and check your inverter's fault history. The specific fault code tells you what the inverter is seeing:

BMS_Lost — the inverter cannot detect the battery at all. The CAN bus link is completely down — either the cable is disconnected or the battery type setting is wrong.
BMS_Internal_Err — usually a DIP switch misconfiguration or a loose CAN cable at the battery management unit.
C1 CAN Fault — a general communication error. The cable may be damaged or the termination resistor may be missing.

Note whether the fault is persistent (showing continuously) or intermittent (appearing and clearing throughout the day). A persistent fault points to a hardware or configuration issue. An intermittent fault often indicates a loose connection or corrosion.

2

Inspect the CAN communication cable

The CAN bus cable is the shielded communication cable running between the X-Hybrid inverter and the battery BMS. It is separate from the DC power cables. Check that it is firmly connected at both ends — at the inverter CAN port and at the battery management unit.

Look for visible damage, kinks, or cuts in the cable jacket. Check the connector pins for signs of corrosion or bending — corroded connectors on the battery motherboard are a known cause of persistent BMS faults and 0% SoC readings. If you have multiple battery modules stacked together, also check the RS485 cables running between them.

A loose CAN cable is the single most common cause of BMS faults, especially on systems where an installer has recently worked on the unit and disturbed the connections.

3

Verify the battery type setting matches your hardware

This is the most important check if the fault appeared after a battery upgrade or inverter replacement. SolaX X-Hybrid inverters have a battery type selection in the settings menu. T-BAT and Triple Power use different BMS communication parameters — if the wrong type is selected, the inverter will not recognise the battery.

Check the inverter display under battery or charger settings. If T-BAT batteries are installed, the setting must say T-BAT. If Triple Power batteries are installed, it must say Triple Power. A mismatch here will cause a persistent BMS fault and the battery will show 0% state of charge despite being physically charged.

This setting may require installer-level access on some firmware versions. If you cannot change it yourself, an engineer can adjust it remotely or on site.

4

Check termination resistor and DIP switch configuration

SolaX battery systems require a 120-ohm termination resistor plugged into the last open CAN communication port. Without this resistor, the CAN bus signal degrades and communication becomes unreliable — even with a single battery unit.

For stacked Triple Power modules, DIP switches on each battery unit must match the total number of modules installed:

• DIP switch 0 — single battery (1 module)
• DIP switch 1 — two batteries stacked
• DIP switch 2 — three batteries stacked

An incorrect DIP switch setting causes the buzzer to beep during self-test and the BMS will not initialise correctly. DIP switch access requires opening the battery enclosure — this is an engineer-level task.

5

Try a controlled power cycle in the correct sequence

If the cable and settings look correct, a controlled power cycle can clear a BMS fault caused by a sync loss. Follow this sequence exactly:

1. Set the inverter to off mode
2. Turn off the battery using its power switch
3. Disconnect the CAN cable at both ends
4. Wait 30 seconds for the BMS to fully power down
5. Reconnect the CAN cable firmly at both ends
6. Turn the battery on — wait two to three minutes for self-test
7. Turn the inverter back on

Monitor SolaX Cloud for the next 15 minutes to see if the fault clears. If the battery LEDs cycle through green during startup, the self-test passed. If the fault returns immediately after restart, do not keep power cycling — the issue needs professional investigation.

6

Book a diagnostic if the fault persists

If the BMS fault persists after checking the cable, verifying the battery type, and performing a power cycle, the issue requires professional diagnosis. At this point the cause may be CAN bus signal integrity failure, corroded connections inside the battery BMS, firmware incompatibility between inverter and battery, or a failed BMS control board.

STS can review your SolaX Cloud fault history remotely to narrow down the root cause before recommending an on-site visit. For battery type mismatches and firmware issues, the fix can often be completed remotely. Remote diagnostic sessions start from £75.

Why T-BAT to Triple Power upgrades are the biggest source of BMS faults in the UK

Between 2020 and 2022, thousands of UK SolaX systems were installed with T-BAT batteries — typically a single T-BAT-5.8 or T-BAT-SYS-HV paired with an X1-Hybrid or X3-Hybrid inverter. As energy prices rose and time-of-use tariffs became more popular, many homeowners upgraded to larger Triple Power battery stacks for greater overnight storage capacity.

The Triple Power upgrade is physically straightforward — the new modules connect to the same inverter via the same CAN bus interface. But the inverter's battery type setting must be changed from T-BAT to Triple Power, and if multiple Triple Power modules are stacked, each module needs its DIP switch set correctly and the RS485 inter-module cables installed. Installers who are unfamiliar with SolaX — or who are rushing to complete the job — sometimes skip the battery type change in the inverter settings. The result is a system that looks correctly installed but immediately reports a BMS communication fault.

The same issue occurs in reverse when inverters are replaced under warranty. The replacement inverter arrives with default battery settings, and if the commissioning engineer does not set the correct battery type, the BMS fault appears from the first power-on. STS sees this pattern regularly on UK systems, and in most cases the fix is a single settings change — no hardware replacement needed.

Reference

SolaX battery LED status indicators

Green (steady)
Normal operation

Battery is communicating with the inverter and operating normally. Master LED steady green, slave LEDs flash green every five seconds.

Orange (flash)
BMS protection active

On for one second, off for four seconds. The battery is protecting itself from an abnormal condition — over-temperature, over-voltage, or under-voltage. May clear on its own or indicate a developing fault.

Red (solid/flash)
Fault state

Red LED on for ten minutes then flickering indicates a fault that needs investigation. The BMS has detected a condition it cannot resolve automatically. Check SolaX Cloud for the specific fault code.

Buzzer beeps
DIP switch or self-test failure

Beeping during power-on indicates the DIP switch configuration does not match the number of modules installed, or the BMS self-test has failed. Check DIP switch positions and inter-module cables.

FAQ

BMS communication faults — common questions

A BMS communication fault means the CAN bus link between the SolaX X-Hybrid inverter and the T-BAT or Triple Power battery has been lost. The most common causes are a loose or damaged CAN cable, the wrong battery type selected in the inverter settings, a missing termination resistor, or incorrect DIP switch configuration on stacked modules. On systems where an installer has recently worked, the cable may have been disturbed. On systems upgraded from T-BAT to Triple Power, the battery type setting is frequently left on the old value.
A battery showing zero percent despite being physically charged almost always indicates a BMS communication fault. The inverter cannot read the actual state of charge because the CAN bus link is down. The most common cause is the wrong battery type selected in the inverter — particularly after a Triple Power upgrade where the setting was left on T-BAT. Corroded CAN cable connectors and a failed BMS control board can also cause this. The battery itself is usually fine — it is the communication path that needs fixing.
You can check and reseat the CAN communication cable at both ends, which resolves many faults caused by loose connections. You can also perform a controlled power cycle — turn off the inverter, then the battery, disconnect and reconnect the CAN cable, then restart in the correct order. However, changing the battery type setting, adjusting DIP switches, checking the termination resistor, and updating firmware all require installer-level access or technical knowledge. If reseating the cable and power cycling do not clear the fault, professional diagnosis is recommended.
Green LED steady or flashing every five seconds means normal operation. Orange LED flashing on for one second then off for four seconds means BMS protection is active — the battery is protecting itself from an abnormal condition. Red LED on for ten minutes then flickering means a fault state that needs investigation. If the buzzer beeps during power-on, this indicates a DIP switch misconfiguration or a self-test failure. On stacked systems, the master battery shows overall status while slave units flash green independently during normal operation.
When a T-BAT battery is replaced with Triple Power modules, the inverter's battery type setting must be changed to match. T-BAT and Triple Power use different BMS communication parameters — if the inverter is still set to T-BAT after a Triple Power installation, it will fail to establish a CAN bus connection. The inverter reports a BMS fault and shows zero percent state of charge. This is one of the most common configuration errors on UK SolaX systems, particularly from 2022 and 2023 when many homeowners upgraded their storage capacity.
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We review your SolaX Cloud fault history, identify whether the cause is a cable issue, configuration mismatch, or firmware problem, and guide you to the fix — before booking a site visit.

  • Not affiliated with SolaX Power
  • Free remote diagnostic · no fix, no fee
  • All T-BAT & Triple Power models

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