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!
SolaX BMS Communication Fault — T-BAT & Triple Power Fix
- Not affiliated with SolaX Power
- Free remote diagnostic · no fix, no fee
- All T-BAT & Triple Power models
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.
Book your free remote diagnosticBack to SolaX hubIndependent — not affiliated with SolaX Power.
My 90-year-old father-in-law had a solar system installed nearly three years ago that never worked properly and kept tripping out. Neither the original installer nor GivEnergy could resolve the issues, and we were even pushed towards replacing the system entirely when GivEnergy went bust. I contacted Ron at Solar Tech Support via WhatsApp, and within a few hours he had diagnosed multiple faults — including incorrect wiring that posed a potential fire risk. He carried out a home visit in Nottingham for £295 (including parts), fixed everything, completed firmware updates, and ensured the system was fully operational. Since then, it has worked perfectly. Ron was knowledgeable, responsive, and took the time to explain everything clearly. Highly recommended — excellent value and complete peace of mind.
My GivEnergy hybrid inverter + battery system had worked faultlessly for 3 years when it suddenly stopped charging and discharging the battery. On contacting my supplier, who had used a sub-contractor for the installation work, I was provided with an email address at GivEnergy but, as it turned out, this is only for GivEnergy Software who are not able to assist. A Google search led to the Solar Tech Support web site, which contains a wealth of helpful information. I requested a remote solar diagnostic, and after providing Ron access to my inverter, he was able to identify and fix the problem within minutes. I am very impressed by Ron’s expertise and knowledge, which included useful information on the current state of GivEnergy Ltd. I would thoroughly recommend Solar Tech Support.
I reached on behalf of a friend, who had lost control of their battery following a storm. A couple giv energy “dealers” had attempted and said different fixes. None worked. Solar tech support solved it remotely on the first attempt almost instantly. Genuinely a 10/10 service.
I can’t praise this firm enough. After hearing my solar panels rattling in very windy conditions, I contacted Solar Tech (as my installers no longer trade). Ronald was fantastic at explaining what he thought the issue was likely to be. Communication was great throughout keeping me fully updated. The team worked really hard on the day to carry out the necessary work. I can now sleep soundly at night without worrying about the solar panels on my roof. I would thoroughly recommend this firm. Thank you for sorting the problem out.
Our SolarEdge PV system with LG batteries had its first hiccup after 8 years of hard work. The Inverter failed. Fortunately I found Solar-Tech-Support who diagnosed the problem very quickly, ordered a replacement unit and fitted it shortly after we received the unit from SolarEdge. Very thorough and professional approach. Thank you, a solid 5 star recommendation.
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!
My 90-year-old father-in-law had a solar system installed nearly three years ago that never worked properly and kept tripping out. Neither the original installer nor GivEnergy could resolve the issues, and we were even pushed towards replacing the system entirely when GivEnergy went bust. I contacted Ron at Solar Tech Support via WhatsApp, and within a few hours he had diagnosed multiple faults — including incorrect wiring that posed a potential fire risk. He carried out a home visit in Nottingham for £295 (including parts), fixed everything, completed firmware updates, and ensured the system was fully operational. Since then, it has worked perfectly. Ron was knowledgeable, responsive, and took the time to explain everything clearly. Highly recommended — excellent value and complete peace of mind.
My GivEnergy hybrid inverter + battery system had worked faultlessly for 3 years when it suddenly stopped charging and discharging the battery. On contacting my supplier, who had used a sub-contractor for the installation work, I was provided with an email address at GivEnergy but, as it turned out, this is only for GivEnergy Software who are not able to assist. A Google search led to the Solar Tech Support web site, which contains a wealth of helpful information. I requested a remote solar diagnostic, and after providing Ron access to my inverter, he was able to identify and fix the problem within minutes. I am very impressed by Ron’s expertise and knowledge, which included useful information on the current state of GivEnergy Ltd. I would thoroughly recommend Solar Tech Support.
I reached on behalf of a friend, who had lost control of their battery following a storm. A couple giv energy “dealers” had attempted and said different fixes. None worked. Solar tech support solved it remotely on the first attempt almost instantly. Genuinely a 10/10 service.
I can’t praise this firm enough. After hearing my solar panels rattling in very windy conditions, I contacted Solar Tech (as my installers no longer trade). Ronald was fantastic at explaining what he thought the issue was likely to be. Communication was great throughout keeping me fully updated. The team worked really hard on the day to carry out the necessary work. I can now sleep soundly at night without worrying about the solar panels on my roof. I would thoroughly recommend this firm. Thank you for sorting the problem out.
Our SolarEdge PV system with LG batteries had its first hiccup after 8 years of hard work. The Inverter failed. Fortunately I found Solar-Tech-Support who diagnosed the problem very quickly, ordered a replacement unit and fitted it shortly after we received the unit from SolarEdge. Very thorough and professional approach. Thank you, a solid 5 star recommendation.
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.
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:
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.
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.
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.
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:
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.
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:
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.
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 are free — you only pay £75 if we fix it remotely.
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.
SolaX battery LED status indicators
Battery is communicating with the inverter and operating normally. Master LED steady green, slave LEDs flash green every five seconds.
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 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.
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.
BMS communication faults — common questions
BMS fault? We diagnose it remotely.
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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