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!
Battery communication fault
- Battery hardware is often fine
- Firmware mismatch is a common cause
- Do not open battery enclosure
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 serviceSafety: do not open battery or inverter enclosures. Internal DC voltage is dangerous even with AC supply isolated.
⭐⭐⭐⭐⭐ Absolutely Outstanding Service! My GivEnergy system had completely gone down, and unfortunately I was getting absolutely no support from either the original fitter or the supplier. I was left completely stuck with a system that wasn’t working. I contacted Solar Tech Support and they were absolutely brilliant from start to finish. They quickly got to the bottom of the problem, knew exactly what they were doing, and managed to get my entire system back up and running. Hands down, these guys are absolute experts in their field. The level of knowledge, professionalism and customer service was exceptional, especially when I’d already been left without any support elsewhere. If you have a GivEnergy system and you’re struggling with an issue, don’t hesitate to contact Solar Tech Support. I honestly can’t recommend them highly enough. 5 stars all day long! 🌟🌟🌟🌟🌟
Unfortunately, only weeks after Givenergy went into receivership, our system failed. Our installers were unhelpful in the extreme but Solar Tech Support were able to diagnose a terminal problem with our Gen 1 AC3 inverter. They advised regarding the available options and (having decided to buy a replacement Givenergy inverter as the simplest solution) they were able to get us up and running. They made themselves readily available to talk through the process and manage any faults. I would have no problem recommending them.
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.
I had a red status light on my GivEnergy battery pack and Ron at Solar Tech Support was a great help resolving the problem. He was able to do a remote diagnosis of the invertor BMS firmware and hardware and gave very quick practical and professional support. Thanks Rob
Ron is truly a gem. Logged into my GivEnergy system remotely, dignosed a faulty cell in the battery, providing clear explanation, including screen grabs. Offered advice of companies I could use to fix battery. All completed over WhatsApp with clear, precise & friendly comms. Stayed true to company statement/ethos "We dont fix it, you dont pay" and didn't charge me aynthing. 100% recommend if you have any issues with your solar system.
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.
Common causes
Listed from most to least commonly encountered.
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.
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.
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.
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.
Less common. The CAN communication port on the inverter or battery has failed — from power surge, physical damage, or hardware defect. Requires component replacement.
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.
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.
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.
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.
Turn the battery off first, using its own shutdown button. Then turn off the inverter at its AC and DC isolation switches, and open the battery circuit breaker last. The shutdown button stops power flowing, so the breaker is never opened under load. Wait 2 full minutes. Restore in reverse: inverter isolation switches on, wait 30 seconds, then the battery breaker, then the battery button last. Allow 5 minutes for the communication to re-establish. Check whether the fault has cleared in the portal.
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.
Frequently asked questions
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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