After 7 months of not being able to access/control my system following a change of wi-fi provider, followed by the news that GivEnergy had ceased trading i was left high and dry. I was unable to get any help whatsoever from my installer, tried various electrical tradespeople etc but no-one knew how to help me. Changed the Dongle but then couldnt get this change recognised in the inverter. Found Solar Tech Support while researching yet again online. Ronald has been amazing. Responding very quickly to my emails and very knowledgeable on the system. Managed to give us the information we needed to get the Dongle up and running and created me another account which now works as it should. His help has been invaluable. Thank you so much. Reviews I saw from other people said Solar Tech Support are very good, but i would say they are Outstanding!! Thanks again for all your help- Mick & Sandra
Pylontech Fault Code Index
- Battery-only — faults surface through your inverter
- LED indicators and BMS protection events
- US2000C · US3000C · US5000 · Force-L2 · Force-H2
If your Pylontech battery is in protection mode or showing alarms through your inverter, a remote diagnostic identifies the cause and recommends the fix — usually within 30 minutes.
Book free Pylontech diagnosisHow diagnostics workI'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
Had a problem with my GivEnergy battery which seemed to be a calibration issue. My installer was unable to help so contacted Ron at Solar Tech Support who was immensely helpful. He diagnosed, confirmed and fixed the problem remotely and very speedily. Would thoroughly recommend this company for their knowledge and ability.
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.
Ron is one of those rare finds - an engineer's engineer. He insightfully and accurately diagnosed the problems with our GivEnergy system, very quickly, which helped get us back on track. We will be using him again!
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.
LED indicator states
The front panel LEDs are the primary way to identify Pylontech battery status. The RUN LED shows operating state, the ALM LED shows fault conditions, and the SOC LEDs show charge level. These states apply to all US-series models.
RUN LED — solid greenNormal · charging activeRUN LED — slow flash (~3.5s)Normal · idle / standbyRUN LED — fast flash (~1.5s)Normal · discharging activeALM LED — flashing red (~1.5s)Warning · approaching limitALM LED — solid red, all others off Protection mode — battery shut downAll LEDs off — battery appears dead Deep sleep or hardware faultForce-series LED states (Force-L2 & Force-H2)
Force-series batteries use a different LED scheme from the US-series — a STATUS LED on the controller plus blue and orange module LEDs, with no ALM LED. The Force-H2 is a high-voltage DC system: Pylontech's manual restricts anything beyond reading the LEDs and using the normal switches to qualified persons.
STATUS LED — solid orange (Force-L2)Power relay open · will not self-recoverAll 7 module LEDs flashing orange (Force-L2)Address distribution failure · stack will not runSTATUS LED — slow flashing orange at power-on (Force-H2)Self-check failure · system will not connectSTATUS LED — solid orange, module LEDs blue (Force-H2)Communication lost or BMS errorVoltage protection alarms
Voltage alarms trigger when individual cell voltages or the total module voltage exceeds safe limits. These are the most common Pylontech protection events, often caused by incorrect charge settings or cell imbalance.
Cell overvoltage protection Protection mode — charge stoppedCell overvoltage warningALM flashing · charge continuingCell undervoltage protection Protection mode — discharge stoppedCell undervoltage warningALM flashing · discharge continuingModule voltage imbalanceMulti-unit stack · SOC mismatchCurrent protection alarms
Current alarms trigger when charge or discharge current exceeds the battery's rated limits. The US5000 supports up to 100A continuous — exceeding this causes the BMS to shut down the affected direction.
Charge overcurrent protection Protection mode — charge stoppedDischarge overcurrent protection Protection mode — discharge stoppedShort circuit protection Immediate shutdown — do not restartTemperature alarms
Temperature alarms protect the lithium cells from operating outside their safe range. Pylontech US-series batteries operate between 0°C and 50°C for discharge and 0°C to 45°C for charge — exceeding these limits triggers protection.
Charge overtemperature protectionCharge stopped · discharge may continueDischarge overtemperature protectionFull shutdown · above 50°CLow temperature charging protectionCharge stopped · below 0°CTemperature sensor faultBMS internal · sensor disconnectedCommunication faults
Communication faults are the most common Pylontech issue in UK installations. These appear when the inverter cannot talk to the battery BMS over CAN or RS485 — and are often caused by incorrect cabling rather than a fault with the battery itself.
Battery communication fault (CAN)Inverter shows: BMS Lost / Batt Comm FailBattery communication fault (RS485)Inverter shows: No Battery / BMS ErrorMaster battery not setMulti-unit stack · no CAN outputInter-module link cable faultStack comm · link cables between unitsModule & stack faults
Faults specific to multi-module stacks and individual module hardware — internal BMS failures, firmware issues, and charge profile problems that affect the battery independently of the inverter.
BMS internal failure Internal error — firmware or hardwareEarly charge cutoff (80–85%)Not reaching 100% · BMS limitingSOC stuck or inaccurateDisplay shows wrong % · SOC driftMixed stack capacity mismatchDifferent models in one stackCodes shown on the inverter & GX — Pylontech side
Pylontech batteries are battery-only, so many faults first appear as a code on the paired inverter or GX device rather than on the battery itself. The exact wording depends on the inverter brand — these are the strings UK owners most often see on Solis hybrids and Victron systems. Sofar, LuxPower, and Growatt inverters show their own battery codes, covered on those brands' fault-code pages.
Batt_Comm_FAILSolis hybrid · battery CAN data lostBatName-FAILSolis hybrid · wrong battery profileNO-BatterySolis hybrid · 0V on battery terminalsAlarm-BMSSolis hybrid · battery reporting an alarmInternal errorVictron GX · slave modules offlinePylontech faults often appear differently depending on which inverter brand is paired with the battery. If you're seeing an alarm in your inverter's monitoring that you can't match to this list, share the exact alarm text and your inverter brand and we'll identify it. Retrieving the Pylontech log files via BatteryView is the fastest route to a definitive diagnosis.
Internal failure · BMS fault · firmwareFull diagnostic — BMS internal failure, firmware versions, cell balancing, and warranty process.
See US2000C / US3000C / US5000 faultsCAN · RS485 · protocol · DIP switchCable pinout, protocol settings, DIP switches, and brand-specific wiring for GivEnergy, Victron, Solis, and more.
See inverter compatibility & pairingManuals · datasheets · wiringOfficial US-series and Force H2 user manuals, datasheets, and installation guides.
See Pylontech documentsMore Pylontech help
Independent Pylontech battery diagnostics, BMS fault diagnosis, inverter compatibility checks, and charge configuration for US2000, US3000, US5000 and Force.
See Pylontech hubOne module in your Pylontech stack has an amber or red LED. The whole bank has shut down, or capacity has dropped. Free remote diagnostic — no fix, no fee.
See US-series faultsYour Pylontech battery won't communicate with the inverter. The inverter shows a BMS fault, the battery LEDs look normal, and nothing charges or discharges.
See inverter pairingDownload Pylontech datasheets, installation manuals, warranty PDFs, app guides and wiring diagrams. US2000C, US3000C, US5000, and Force H2 batteries.
See documentsPylontech battery fault questions
Battery alarm you can't clear?
Describe the LED state on the battery, what your inverter's monitoring is showing, and when the fault first appeared. We'll analyse the data remotely and tell you whether it needs a settings change, firmware update, or site visit.
- Not affiliated with Pylontech
- No fix, no fee
- Written report with cause and recommended action
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Due to unprecedented demand we’re currently only carrying out on-site work in Yorkshire, and replies are taking up to 7 days. Remote diagnostics continue for the whole UK as normal.
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