STORAGE_WARN_BMS_COM_FAIL or STORAGE_ERROR_BMS_COM_FAIL — or simply show the battery as disconnected. This guide covers every cause in order of likelihood.The exact sequence of events in your inverter's log — what codes appeared, in what order, and when — tells us whether this is a cable fault, firmware issue, or BMS protection event. We can review this remotely.
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Brilliant support to get my solar battery working again. I didn’t expect help on a Saturday but Ron answered the phone, listened and sent me the information I needed to get it going, answered questions etc. A brilliant service I’d happily recommend.
Ron was brilliant. He really tried to help. He spent hours trying to fix our GivEnergy AIO and ultimately it became apparent that it needed parts to fix the BMS management system. As there appears to be no replacement parts available on the market, he gave excellent advice on what options are now available to move forward. He is incredibly helpful and knowledgeable.
Called back within a day and gave good advice.
Ron was extremely helpful and tried his best to repair/reset our GivEnergy inverter remotely. In the event he was unsuccessful but he couldn’t have been more helpful. If you have problems with a GivEnergy system please contact him. Highly recommended
Big thanks to Ron. He was incredibly patient and helpful over the phone, taking the time to walk myself and the installer through every troubleshooting step. Through lots of testing he figured out the issue was definitely a hardware issue, which allows us to consider our next steps. Support fees are clear and they operate a “no fix no fee” policy. It is rare to find that kind of honesty combined with dedicated phone support nowadays. I highly recommend Ron, if you need help with your solar system don’t hesitate to give him a call.
A superb service from Ron who went beyond the normal service received from other Tech support companies. I live abroad and was badly let down when my givenergy system failed (and the company went bankrupt) and the local supplier ran away from the problem. Ron sorted the problem and even accessed specialist coding for the inverter that would not be available for suppliers. Ron also ran a full diagnostic to insure that all was in good working order afterwards. Without Rons support and patient assistance I doubt I would ever have got the system back up and running. Well done and thankyou and you have a customer for the future.
Brilliant support to get my solar battery working again. I didn’t expect help on a Saturday but Ron answered the phone, listened and sent me the information I needed to get it going, answered questions etc. A brilliant service I’d happily recommend.
Ron was brilliant. He really tried to help. He spent hours trying to fix our GivEnergy AIO and ultimately it became apparent that it needed parts to fix the BMS management system. As there appears to be no replacement parts available on the market, he gave excellent advice on what options are now available to move forward. He is incredibly helpful and knowledgeable.
Called back within a day and gave good advice.
Ron was extremely helpful and tried his best to repair/reset our GivEnergy inverter remotely. In the event he was unsuccessful but he couldn’t have been more helpful. If you have problems with a GivEnergy system please contact him. Highly recommended
Big thanks to Ron. He was incredibly patient and helpful over the phone, taking the time to walk myself and the installer through every troubleshooting step. Through lots of testing he figured out the issue was definitely a hardware issue, which allows us to consider our next steps. Support fees are clear and they operate a “no fix no fee” policy. It is rare to find that kind of honesty combined with dedicated phone support nowadays. I highly recommend Ron, if you need help with your solar system don’t hesitate to give him a call.
A superb service from Ron who went beyond the normal service received from other Tech support companies. I live abroad and was badly let down when my givenergy system failed (and the company went bankrupt) and the local supplier ran away from the problem. Ron sorted the problem and even accessed specialist coding for the inverter that would not be available for suppliers. Ron also ran a full diagnostic to insure that all was in good working order afterwards. Without Rons support and patient assistance I doubt I would ever have got the system back up and running. Well done and thankyou and you have a customer for the future.
CAN bus is the communication protocol GivEnergy uses between the inverter and battery. It carries state of charge data, charge/discharge commands, temperature readings, and protection signals. Without it, the inverter cannot safely operate the battery.
A CAN fault doesn't necessarily mean the battery is damaged. It means the communication channel has been interrupted. The battery cells themselves are usually fine — the system just can't talk to them. This distinction matters for whether the fix is remote or on-site.
The portal event log will show STORAGE_WARN_BMS_COM_FAIL (warning level) or STORAGE_ERROR_BMS_COM_FAIL (error level). The battery may show as disconnected in the portal dashboard, with SoC reading zero or N/A.
Two checks that take under a minute and eliminate the most common causes immediately.
The GivEnergy battery has a power button on the side panel. If this has been accidentally turned off — after a power cut, during a house move, or by a household member — the battery will appear as disconnected and trigger a CAN fault. Press and hold the button until you hear a beep and the LED indicators illuminate.
The CAN communication cable runs between a socket on the inverter (underside) and a socket on the battery (typically labelled BMS or CAN). Check that the connector is fully seated at both ends — it should click firmly into place. A partially connected cable is a common cause of intermittent CAN faults, particularly on newer installations where cables may not have been fully seated at commissioning.
Many CAN faults — particularly those triggered by power interruptions, brief grid outages, or software glitches — clear themselves after a controlled restart of both the inverter and battery. This should always be the first active step after the quick checks above.
Find the green or red handled MCB switch between the inverter and battery. Move it to the DOWN / OFF position. This isolates DC power between the two units before shutdown.
Press and hold the button on the side of the battery until the LEDs go out. The battery is now off. Leave it off for at least 60 seconds — this allows the BMS capacitors to discharge and clears any latched fault states.
The AC isolator is the switch below the inverter on the wall. Turn this off. Wait 60 seconds. Both the inverter and battery are now fully powered down.
Turn the AC isolator back on first. The inverter will begin its startup sequence. Then turn the battery on using the side button — wait for the LED indicators to stabilise (typically green). Then move the DC MCB back to the UP / ON position.
BMS_COM_FAIL code has cleared. If the fault reappears within minutes of restarting, there is a persistent underlying cause — continue through this guide.
If the power cycle doesn't resolve the fault, the CAN cable between the inverter and battery is the next suspect. This is a physical cable and physical faults require a site visit to rectify — but a remote diagnostic can confirm the cable is the likely cause first.
The GivEnergy inverter and battery run separate firmware versions that must be compatible with each other. If the inverter firmware is updated but the battery firmware isn't — or vice versa — the CAN protocol version can become incompatible and communication breaks.
Go to givenergy.cloud → My Inverter → Software. The current firmware version is shown here. GivEnergy will also show whether an update is available for the inverter.
Battery firmware version is visible in the portal under My Inverter → Battery details. If the battery firmware shows as outdated or mismatched, it needs updating. Check the GivEnergy knowledge base for the firmware compatibility matrix for your models.
If the inverter firmware needs updating, this can be done remotely via the portal. Go to My Inverter → Software and click Update if an update is available. The update takes 5–30 minutes — do not turn the system off during this process. If the update appears stuck after an hour, restart the inverter.
Battery firmware updates are done locally via a USB stick inserted into the battery's internal USB port. This requires opening the front cover of the battery, which is an installer task — do not attempt this yourself. Contact GivEnergy support to obtain the correct BMS_ARM.bin file and arrange for an engineer visit if a battery firmware update is required.
The Battery Management System (BMS) can lock the battery into a protection state in response to events like over-voltage, under-voltage, over-temperature, or a short-circuit detection. When locked in a protection state, the BMS stops responding to the inverter's CAN requests — which is reported as a communication fault even though the cable is fine.
Some BMS protection events clear themselves after a controlled power cycle (see the power cycle section above). Others — particularly over-discharge events — require the battery to be recovered with a slow charge before the BMS will accept normal operation. Contact GivEnergy support if a power cycle doesn't clear the fault and a BMS protection event is suspected.
See the red light / battery alarm guide →If all the above have been checked and ruled out, the fault may be a hardware failure — either the CAN interface on the inverter, or the BMS board inside the battery. These are warranty-eligible repairs on systems within the manufacturer warranty period.
The CAN transceiver on the inverter PCB can fail — particularly after lightning-induced surges or sustained over-voltage events. Signs include persistent BMS_COM_FAIL with a known-good cable, and the fault appearing on a new battery if the battery is swapped as a test.
GivEnergy inverter warranty: typically 5–10 years depending on model. Contact GivEnergy with a written diagnostic report to support a warranty claim.
The BMS board inside the battery can fail independently of the battery cells. This is a hardware fault inside the enclosure and requires an engineer visit. Do not open the battery yourself. Battery warranty is typically 5–10 years and covers BMS hardware failures.
A remote diagnostic and written engineer report identifying the fault strengthens any GivEnergy warranty claim significantly.
A written engineer report identifying the fault type and cause significantly strengthens GivEnergy warranty submissions. We can provide this as part of a remote diagnostic session.
Battery alarm states and what each flash pattern means.
Firmware updates causing new faults or resetting settings.
Battery not charging overnight — system mode and CT clamp causes.
Full index of GivEnergy fault codes and their meanings.
This is a brand-specific version of our general battery communication fault guide, which covers all brands.
Tell us what the portal shows, when the fault appeared, and what you've already tried. We'll review your event log and identify whether this is a cable, firmware, BMS, or hardware fault — before recommending any site visit.
I’ve worked on hundreds of GivEnergy systems and know the kit inside out. If yours is playing up, my promise is simple — no fix, no fee: just £75 if we fix it, free if we don’t.
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