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. 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.
Alert & LED index · Powerwall 2 · Powerwall 3 · Gateway
Tesla Powerwall Fault & Alert Guide
Every Tesla Powerwall app alert, LED indicator state and Gateway error — what each one means, the most likely cause, and what to do next. Covers Powerwall 2, Powerwall+, Powerwall 3 and the Backup Gateway 2. Tesla publishes no Powerwall fault-code list, so nothing here is invented to fill that gap: the LED tables are Tesla's own, split by generation, and anything that is our wording rather than Tesla's is labelled as such.
Free remote diagnostic £125 only if we fix it remotely
- Alerts shown in the Tesla app
- LED states + Gateway status
- Powerwall 2 · Powerwall 3 · PW+
customer · Apr 2026 Trustpilot
Genius when it comes to solar and off grid installations we spent days trying to work out what was causing our problems and Ron resolved it in less than an hour! Cant reccomend enough
Ben Carroll · Aug 2026 Google
Fantastic support. We have a Givenergy system where one of our batteries was not working. Ronald successfully helped us get it back up. His perseverance was amazing….and it shows what REAL customer service means. Can’t thank you enough Ron!
Martin · Aug 2026 Google
Ron is a life saver sorted out a connectivity problem and had to replace one of my inverters all good now so I can stop stressing. Thank you again
Glenn Hempstead · Oct 2026 Google
Brilliant service from Ron - our GivEnergy inverter stopped working on Tuesday what a nightmare seen as the company who installed it are no longer in business. Through social media I found STS (Ron) he had a new inverter and it was fitted and working by Friday - what I thought was going to be a nightmare turned out not to be!!! Great guy great company - def my go to now for anything solar related - Thank you so much
Jane Thomas · Oct 2026 Google
⭐⭐⭐⭐⭐ 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! 🌟🌟🌟🌟🌟
Mr Smith · Aug 2026 Google
LED states — Powerwall 2
Tesla's Powerwall 2 owner manual describes the LED on the right side of the unit by pattern only. It publishes no colour table for Powerwall 2 at all — “green” is field shorthand that has spread through owner forums, not Tesla's wording. The pattern is what carries the meaning, and it is the only diagnostic you can read with no app, no internet and no login.
On (solid)Normal · idleTesla's wording: “System idle, no faults.” The Powerwall is enabled and healthy but not currently moving energy in either direction. No action required.
On (fading)Normal · activeTesla's wording: “System enabled and charging or discharging.” The slow fade tracks energy flow — the battery is storing solar, supplying the house, or following a time-of-use schedule. No action required.
On (flashing) Fault presentTesla's current owner manual gives one meaning for a flashing Powerwall 2 LED: fault present. This is the row most commonly got wrong online, including by us until we rechecked it. Tesla's 2017 manual said a flashing LED meant “Powerwall enabled / No communication with the Gateway”, and that superseded wording is still mirrored on dozens of sites. If you act on it you will spend your time restarting a router while a fault sits unreported. Treat a flashing LED as a fault: note what the Tesla app says, then get it diagnosed.
OffNot enabled · no powerTesla's wording: “System not enabled or switched off.” Check the On/Off switch on the side of the Powerwall and the circuit breaker feeding it. If both are on and the LED stays dark, the unit is not receiving power or has an internal supply fault — that needs an engineer, not a reset.
LED states — Powerwall+
Powerwall+ is the only Powerwall whose owner-visible LED tells you how serious the fault is, and it does it through flash speed. Worth knowing if you have one — though we have not established that Powerwall+ was ever sold in the UK, and Tesla makes no statement either way. If you have one here, tell us; we are collecting evidence.
On (flashing slowly)Fault · safe stateTesla's wording: “Powerwall+ faulted at < 30 V solar (safe).” The unit has faulted with the PV array below 30 V, which Tesla classes as the safe condition. Still a fault and still needs diagnosing — but the slow flash is telling you it has shut down in a controlled way.
On (flashing rapidly) Abnormal fault presentTesla's wording: “Abnormal fault present.” The fast flash is the escalated state. Turn off the Powerwall On/Off switch and get it looked at — do not keep power-cycling it.
On (solid) / On (fading)Normal · idle or activeSolid is “idle, no faults”. Fading is “enabled and charging or discharging, or generating solar energy” — the extra clause is the difference from Powerwall 2, because Powerwall+ has the solar inverter built in.
OffNot enabled · no powerTesla's wording: “not enabled or switched off.” Same checks as Powerwall 2 — side switch, then breaker.
LED states — Powerwall 3
Powerwall 3 uses the illuminated logo on the front as its status LED, and its table shares nothing with Powerwall 2's. There is no green state. If you have read about green or light-blue Powerwall 3 LEDs, those are the internal Tesla Asset Controller LEDs — Tesla's own installer guide notes they “are not visible when the Powerwall 3 front cover is installed”, so as an owner you cannot see them. Note also that Powerwall 3 Expansion units have no LED indicator and their logo never lights.
Solid whiteNormal · operatingTesla's wording: “Normal operation.” Nothing to do.
Flashing whiteNormal · idle, heading for sleepTesla's wording: “Powerwall 3 is idle. Will enter sleep state if no actions in progress.” This is not a fault. From software 24.4 onward Powerwall 3 sleeps after ten minutes idle and wakes itself every two hours — see the sleep-state entry below before assuming something has failed.
OffOff or asleepTesla's wording: “Powerwall 3 is off or in sleep state.” An unlit logo on a system that is otherwise behaving is most likely sleep, not failure. To wake it deliberately: turn the Enable switch OFF, wait three seconds, turn it ON — it boots in about 90 seconds.
Flashing red Inverter faultTesla's owner manual gives one meaning: inverter fault. The installer guide is more specific — “Inverter (PWS) fault, e.g. AFCI or GFCI”, i.e. arc-fault or ground-fault detection on the PV side. It does not mean a firmware update is running: during an update it is internal TACO LED 2 that may flash red, and that LED is behind the front cover where you cannot see it. A flashing red logo is a fault. Turn off the Enable switch and get it diagnosed.
Tesla app alerts
The Tesla app delivers push notifications and in-app alerts when your Powerwall changes state or detects an issue. You need an active internet connection on both your phone and the Gateway to receive these. Some alerts are informational (e.g. going off-grid during a power cut), while others require action.
Breaker OpenAlert · electricalThe circuit breaker connecting the Powerwall to your home's electrical system is in the off position. The Powerwall cannot charge, discharge, or provide backup while the breaker is open. Locate the breaker in your consumer unit that feeds the Powerwall circuit and switch it back on. If the breaker trips again immediately, there may be a wiring fault on the Powerwall circuit that needs an electrician.
Side Switch OffAlert · manualThe enable switch on the side of the Powerwall unit has been turned off. The Powerwall will not power your home. On Powerwall+ and Powerwall 3, solar generation will also stop because the inverter is integrated. On Powerwall 2, solar may continue generating through your separate inverter. Check the switch on the right-hand side of the unit and flip it to the on position.
Rapid Shutdown Device OffAlert · safety switchThe Tesla app banner reads "Powerwall or PV Inverter will not operate". A rapid shutdown device fitted to your system has been switched off, so the Powerwall will not power your home. Solar may still generate depending on your system configuration. Tesla notes the device may look like a red emergency-stop button or a separate marked switch near the Powerwall or solar inverter. Rapid shutdown initiators are not a UK regulatory requirement and presence varies by install, so first check whether your installer fitted one and whether anyone switched it off, deliberately or during building work. If you are not expecting it to be off, or you cannot find any such device on your installation, contact your installer to confirm whether it is expected or needs a service visit. Do not force or dismantle the device.
Powerwall Disabled — Service Required Internal fault — contact installerAn internal fault has been detected and the Powerwall has shut itself down. This is one of the most serious alerts. Common causes include an internal cell failure, a DC stage fault in the power conversion hardware, or a ground fault detected during the insulation self-test. Turn off the enable switch and contact your installer or Tesla support. This typically requires a site visit and may result in a warranty replacement — a power cycle will not fix it.
Solar Production LimitedAlert · solar faultThe Tesla app banner reads "Service Required - Fault Detected". Tesla's description is that one of your inverters may not be producing solar due to a fault detected with your solar system. On Powerwall+ and Powerwall 3 this points at the integrated solar inverter. Tesla's official guidance is to contact your installer to schedule a site visit. Before you do, note what the app shows for solar production (zero, or just reduced), whether the alert appeared after a storm or a firmware update, and whether the LED state on the unit has changed. Do not touch DC isolators or wiring. A remote review of the app data can often tell whether it is one string, the whole inverter, or a monitoring artefact before anyone books a visit.
Low Energy LockoutUnofficial name · battery ran flat"Low Energy Lockout" is widely used by owners and installers, but it is not an alert name Tesla uses in the app or in its official support documentation. When a Powerwall runs flat during an extended power cut, the alerts you will actually see are Tesla's three-step sequence, covered later in this section: "Waiting for Solar", then "Waiting for User Input", then "Waiting for Grid". The underlying concern is real. Tesla's own Powerwall 3 documentation warns that a battery allowed to drain to 0% state of energy cannot be recovered without intervention, which is why the system shuts itself down and waits rather than running completely flat. If your Powerwall has sat empty and will not restart once the grid returns, stop power cycling it and contact your installer or Tesla support promptly.
Powerwall Low EnergyAlert · informationalThe Powerwall charge level is low. If you are off-grid during a power cut, reduce household loads to extend your backup duration. In normal grid-connected operation, this alert means the battery has discharged to near the backup reserve threshold and will stop discharging to preserve backup capacity. The system will recharge from solar or the grid depending on your mode settings. No action needed unless you are in a power cut.
Powerwall Very Low EnergyAlert · urgentThe Powerwall is critically low on energy with very limited backup time remaining. Immediately reduce your home's power consumption — switch off non-essential appliances, heating, and high-draw devices. If the grid is still available, the system will recharge. If you are off-grid during a power cut, prioritise only essential loads like lights and the fridge to extend the remaining backup as long as possible.
Waiting for SolarAlert · off-grid shutdownDuring an extended power cut the Powerwall has run very low on energy and has stopped providing power. The push notification reads "Powerwall is very low on energy and stopped providing power. Powerwall will resume operation during daylight hours to charge from solar." The system checks hourly and restarts on its own once there is enough solar to power your home and recharge the battery at the same time. Help it succeed by switching off high-draw appliances such as kettles, ovens, immersion heaters, and tumble dryers. Tesla also notes you can restart manually by toggling the on/off switch on the side of the unit once solar is available.
Waiting for User InputAlert · manual restart neededSent after "Waiting for Solar" when the hourly automatic retries could not find enough solar to resume operation. The push notification reads "Automatic retries did not have sufficient solar to resume Powerwall operation. Reduce your load and manually resume when solar is present by toggling on/off switch." Turn off everything non-essential, wait for decent daylight on the panels, then toggle the enable switch on the side of the unit (right side on Powerwall 2, left side on Powerwall 3). If it shuts down again straight away, your loads are still too high or solar is still insufficient. If the grid has returned and the system still will not resume, the fault needs proper investigation.
Waiting for GridAlert · battery emptyThe final alert in the low-energy sequence, sent after "Waiting for User Input". The push notification reads "Powerwall is empty and has shut down. Powerwall will be unavailable and is waiting for the grid to return." The battery is fully depleted and can no longer restart from solar. This is the designed deep-discharge protection state, so there is nothing to fix on the unit itself. When mains power returns, the Powerwall recharges and resumes automatically. Check the Tesla app a few hours after the grid comes back to confirm charging has resumed. If the grid is back but the unit stays dead, with the LED off and no app data, do not open or probe anything. A unit stuck at 0% can need professional recovery.
Powerwall OverloadedAlert · load managementThe load on the backed-up circuit exceeds what the Powerwall can deliver. Each Powerwall unit supports up to 5kW continuous output — if your household demand exceeds this during a power cut, the system overloads and disconnects. You may hear audible clicking as it retries. Reduce the load by switching off high-draw appliances like kettles, ovens, and immersion heaters. The Powerwall will automatically retry within two minutes once the load drops. In multi-Powerwall systems, the combined output is higher but the total load must still stay within the aggregate rating.
Calibration in ProgressAlert · maintenance"Calibration in Progress" is the banner name Tesla uses in the app; owners often shorten it to calibrating. The Powerwall is performing a routine battery calibration. During calibration, the system may charge and discharge the battery through a full cycle to recalibrate the state-of-charge reading. Tesla publishes no duration for it, so treat any specific figure you read (ours included, until we removed it) as guesswork; it is normal maintenance behaviour either way. The SOC percentage in the app may appear inaccurate during this period. No action required — the system will return to normal operation after calibration completes.
Storm WatchAlert · informationalA severe weather event has been forecast for your area and the Powerwall is charging to maximum capacity to prepare for a potential power cut. Storm Watch temporarily overrides your normal operating mode and prioritises backup readiness. Once the storm warning passes, the system returns to your previous settings. This is an automatic feature that can be enabled or disabled in the Tesla app under Powerwall settings.
Battery & thermal faults
Battery faults relate to the internal cells, temperature management, and power conversion hardware inside the Powerwall unit. Tesla's BMS monitors cell voltages, temperatures, and insulation resistance continuously. Most battery faults require professional attention — the Powerwall is a sealed unit and not user-serviceable.
Internal Fault / Battery Fault Sealed unit — professional service requiredThe Powerwall's internal diagnostics have detected a fault within the battery pack or power electronics. This could be a cell failure, a manufacturing defect that has developed over time, or degradation. Owners commonly describe this as “Internal Fault Detected”; that exact string is not one we can find in any Tesla source, so treat it as owner shorthand. Battery Fault is a real Tesla name — it appears in Tesla's installer alert list as Critical, “one or more inverter blocks is in a faulted state”. Turn off the enable switch on the side of the unit. The Powerwall is a sealed, non-serviceable unit — do not attempt to open it. Contact your installer to initiate a warranty claim with Tesla.
Battery Over-temperatureThermal · environmentThe internal battery temperature has exceeded the safe operating limit — but the cooling system, and therefore the advice, differs by generation. Powerwall 2 is liquid-cooled and holds up to 2.3 litres of coolant; Tesla's owner manual carries a coolant-leak procedure, and a failed cooling circuit is a real cause here. Powerwall 3 is air-cooled — it has an air intake and an air exhaust and no coolant at all, so blocked clearance matters and a coolant fault is not possible. Do not assume direct sunlight is the problem on a Powerwall 3: Tesla's UK datasheet states it is “designed to operate in all climates and in direct sunlight, from temperatures of -20°C to 50°C”, with performance de-rated above 40°C. On both generations the operating range is -20°C to 50°C and the system resumes once temperature falls back inside it.
Battery Under-temperatureThermal · cold weatherThe battery temperature is below the minimum for safe charging. Worth knowing before you call it a fault: Tesla's UK Powerwall 2 datasheet gives an optimum range of 0°C to 30°C and notes that “performance may be de-rated at operating temperatures below 10°C” — so a British garage in January can legitimately look sluggish without anything being wrong. Powerwall has a built-in heater that activates in cold conditions, but in extreme cold the heater may not raise the temperature fast enough. The system will wait until the cells reach a safe temperature before resuming charge. Discharge may continue at a reduced rate in cold conditions. If the unit is installed outdoors or in an unheated outbuilding in the UK, sub-zero winter nights can trigger this regularly.
DC Stage Fault Power conversion failure <span class="text-white/40">(our term)</span>Not a Tesla alert name. Tesla's nearest published equivalents are the installer-side Power Converter Failure and Powerwall Inverter Failure, both of which Tesla classes RMA — “unit needs replacement”. The DC-to-AC power conversion stage inside the Powerwall has failed. This is the inverter circuitry that converts stored DC energy into usable AC power. A DC stage fault means the Powerwall cannot charge or discharge. This is a hardware failure that requires professional service — typically a warranty replacement of the unit. Turn off the enable switch and contact your installer.
Powerwall BalancingMulti-unit · normalIn multi-Powerwall installations, the system is balancing the charge level between units. This is normal behaviour that occurs automatically when the state of charge differs significantly between Powerwall units. Balancing completes without intervention. Be wary of the specific durations quoted around the web, including the “six hours” we used to print here: Tesla publishes no figure for it. During balancing, the system may temporarily reduce its available capacity. No action required.
Gateway & communication faults
The Backup Gateway 2 (or Backup Switch on Powerwall 3) is the brain of the system — it manages grid switching, energy monitoring, and cloud connectivity. If the Gateway goes offline, you lose monitoring and some control features, but the Powerwall typically continues operating locally.
Gateway OfflineCommunication · networkThe Gateway has lost its internet connection. The Tesla app shows a greyed-out or blank power flow screen, and the Gateway may be making a beeping sound. Check that your router is working and the internet connection is active. Verify the Ethernet cable between the Gateway and router is firmly plugged in at both ends (if using wired connection). If connected via Wi-Fi, check the Gateway has not lost the Wi-Fi password after a router change. Tesla states the Gateway is “not user-serviceable” and warns against opening its deadfront cover, so do not go looking for the reset button — if a restart is needed, use the breaker power cycle described under Communication Error / No Data below.
Communication Error / No DataCommunication · PW to GatewayThe Powerwall cannot communicate with the Gateway or the Tesla cloud. The system may still charge and discharge locally, but you will not see live data in the app. Do not open the Gateway to press its reset button — Tesla states that “Powerwall and the Gateway are not user-serviceable”, and “do not open the deadfront cover inside the Gateway. Exposed wiring can present a risk of electrical shock.” The RESET button is documented only in the installer manual. The owner-safe restart is a breaker power cycle in Tesla's stated order: turn the Powerwall On/Off switch off, then the Powerwall AC breaker, then the Gateway AC breaker; wait at least one minute; then reverse the order. Tesla adds: “on Powerwall systems with interconnected solar, always turn off the solar inverter or disconnect the solar source before turning off the Powerwall unit.” If the Gateway Wi-Fi name or password changed when you swapped router, it needs reconnecting via the Tesla app rather than power-cycling. If it still won't connect, we set it up on site, from £195: we connect it to your WiFi, set up your router, including a separate 2.4 GHz network if it needs one, and check it's reporting.
Gateway BeepingCommunication · offline <span class="text-white/40">(owner term)</span>Not a Tesla alert name. Tesla's customer material acknowledges a beeping Gateway but publishes no table of beep patterns, so nobody, us included, can tell you what a specific beep sequence means. What we can say: a beeping Gateway is an audible connectivity alert. Check the internet connection and the Gateway supply. If it keeps beeping, use the owner-safe breaker power cycle described above — Tesla's order, and at least one minute, not thirty seconds. Persistent beeping afterwards points at the Gateway's communication hardware and needs an engineer. If you can record the pattern, send it to us; we are building an evidence base Tesla has never published.
Firmware Update in ProgressSystem · updateTesla pushes firmware updates automatically over the internet. The system may be temporarily unavailable. A common misreading: on Powerwall 3 the logo LED flashing red means an inverter fault, not an update — it is the internal TACO LED 2, behind the front cover and invisible to you, that may flash red during an update. Do not turn off the Powerwall or Gateway mid-update; interrupting it can leave the system partially updated and needing professional recovery. Tesla publishes no expected duration, so we no longer quote one — if the system stays unavailable long enough to worry you, that is the point to ask.
Firmware Update FailedSystem · softwareA firmware update did not complete successfully. The system may repeatedly go offline for brief periods while retrying the update. Ensure the Gateway has a strong, stable internet connection — updates can fail over weak Wi-Fi. If using Wi-Fi, consider connecting the Gateway via Ethernet for the duration of the update. If the update continues to fail after ensuring good connectivity, contact Tesla support — they can push the update remotely or schedule a service visit.
Grid & backup faults
Grid and backup alerts relate to how the Powerwall interacts with the mains supply and provides emergency backup power during outages. The Backup Gateway continuously monitors grid voltage and frequency and will island your home (disconnect from the grid) if conditions fall outside safe parameters.
Going Off-Grid / Island DetectedGrid · power cutThe Powerwall has detected a grid outage or grid voltage/frequency outside safe limits and has disconnected your home from the mains. Your home is now running entirely on Powerwall battery and solar (if available). This is normal backup behaviour. The Powerwall may discharge below your set backup reserve during an extended outage. Reduce household loads to extend backup duration. The system will automatically reconnect to the grid when it detects stable power has returned.
Grid Out of ComplianceGrid · voltage or frequency <span class="text-white/40">(our term)</span>Not a Tesla alert name — it is our description of a real condition. Tesla's own installer tooling has a related 7-day diagnostic called Grid Compliance and an alert called Grid Resynchronization Failed, neither of which the owner can see. The grid voltage or frequency is outside the Powerwall's compliance window but has not fully dropped out. The system may hesitate to island or may island briefly and reconnect. If you notice the Powerwall did not activate during a power cut, "grid out of compliance" conditions just before the outage may have prevented the transfer. This is a known edge case — the system needs a clean transition. If your grid supply is consistently unstable, contact your DNO to report the issue.
Backup Failed / No Backup During OutageBackup · did not activateThe grid went down but the Powerwall did not provide backup power. Possible causes include the Powerwall having insufficient charge (below the backup reserve), the Gateway transfer switch failing to island the home, or a breaker being open on the backup circuit. Check that the Powerwall was charged above the backup reserve threshold at the time of the outage. Verify the Gateway breaker and Powerwall breaker are both on. If the system was charged and breakers were on but backup still failed, the Gateway transfer switch may need investigation.
Grid ReconnectedGrid · informationalThe grid supply has returned and the Powerwall has reconnected your home to the mains. The system will resume its normal operating mode — self-powered, time-based control, or whatever mode you had selected. The Powerwall will begin recharging from solar or grid depending on settings. No action required. This notification confirms the power cut is over and your system is back to normal.
Powerwall 3 solar-specific faults
Powerwall 3 has an integrated solar inverter, so it has additional fault types related to PV strings that Powerwall 2 does not have. These faults only appear on Powerwall 3 and Powerwall+ systems where solar panels connect directly to the unit.
Isolation Self-Test FailureSolar · PV string insulationTesla's installer guide names two alerts here, PV Isolation Total and PV Isolation 24Hr Lockout, and both are about the PV strings rather than the battery. We had this filed under battery faults until we rechecked it; it belongs here. The Powerwall 3 measures insulation resistance between the PV conductors and earth, and disables the solar side if it reads low. Tesla's listed causes are a damaged module or MCI, a nicked or cut wire touching conduit, a wire pinched by mounting hardware, and mixed-up strings. The field test is an insulation tester at the 1000 V setting, positive-to-earth and negative-to-earth, with a pass criterion of greater than 1 MΩ. Tesla does publish a lower trip threshold in its installer documentation, but the figures circulating online are US inverter models and we are not printing a number until we have confirmed the UK one. This is wet-weather-sensitive: an insulation fault that clears on a dry afternoon and returns after rain is a damaged cable, not a ghost.
Arc Fault Detected DC arc — safety shutdownThe Powerwall 3's arc fault circuit interrupter (AFCI) has detected a potential DC arc on a solar string. This is a fire safety mechanism. The system shuts down the affected string. Inspect the DC wiring for damaged cables, loose MC4 connectors, burn marks, or poor junction box connections. If five arc fault alerts occur within 24 hours, the system enters Arc Fault Lockout — a full inspection of the DC wiring must be performed before the system can be re-enabled. Do not ignore arc faults — they indicate a genuine fire risk.
Arc Fault Lockout Repeated arcs — system lockedFive or more arc fault alerts have occurred within 24 hours. The system has entered lockout mode and will not restart until the DC wiring has been professionally inspected and the issue remediated. A qualified electrician or solar engineer must physically inspect every MC4 connection, cable run, isolator, and junction box on the affected string. After repair, the lockout must be cleared through the commissioning tool. This is not a reset-and-hope situation — the underlying wiring fault must be found and fixed.
PV Input OvervoltageSolar · string voltage <span class="text-white/40">(our term)</span>The open-circuit voltage on a PV string connected to the Powerwall 3 exceeds the maximum DC input rating. Too many panels are connected in series on that string. Measure the string Voc with a multimeter — on cold mornings, voltage rises significantly. Tesla's UK Powerwall 3 datasheet gives the numbers to measure against: PV DC input voltage range 60–550 V DC, MPPT range 60–480 V DC, withstand voltage 600 V DC, three MPPTs at 26 A Imp / 30 A Isc each, maximum solar STC input 20 kW. If cold-morning Voc exceeds 550 V, the string must be reconfigured with fewer panels in series. Do not continue operating with an over-voltage string — it can damage the internal inverter hardware.
PV Ground FaultSolar · insulationA ground fault has been detected on the PV array connected to the Powerwall 3. The insulation resistance between the solar string and earth is below the safety threshold. Check DC cables for physical damage, inspect MC4 connectors for moisture ingress, and examine the cable runs for anything that could compromise insulation. If the fault only appears in wet weather, a connector joint or cable entry point is the likely culprit. Disconnect strings individually to isolate which one has the fault.
Powerwall 3 commissioning & system states
These alerts and states are specific to Powerwall 3 and surface in Tesla One, the installer's commissioning tool, rather than in the owner app. They matter to homeowners because the visible symptom is usually a unit that looks dead, will not start, or produces nothing from one solar string. None of them is owner-serviceable, but knowing the name helps you have an informed conversation with your installer.
MCI Self-Test FailurePW3 · string safety switchA commissioning alert shown in Tesla One as "Alert: MCI Self-Test Failure". The Powerwall 3 is failing the self-test of an MCI (mid-circuit interrupter), the rapid-shutdown safety switch Tesla fits to every PV string, including on UK systems where rapid shutdown rules do not apply. Tesla's documented symptom is a string that shows voltage during the self-tests but then sits greyed out at 0V once they complete, so to an owner this usually presents as one string producing nothing. The fix is installer work: Tesla provides MCI diode and resistance health tests plus an open-air voltage test to identify the faulty MCI, which is then replaced. Do not touch the DC string wiring. Note which string shows nothing in any data you can see and contact your installer.
Inverter Relay Self-Test FailurePW3 · inverter relayA commissioning alert shown in Tesla One as "Alert: Inverter Relay Self-Test Failure". The Powerwall 3 is failing the self-test of the relay that connects its integrated inverter to the AC side. Tesla's documented troubleshooting is installer-side: confirm the system has been started, perform a Stop System then Start System, and confirm the AC State reads Active during the relay self-test. Likely possibilities include a system that was never started after install or service, an AC-side supply issue, or a genuinely faulty relay inside the sealed unit. If your system is newly installed or just serviced and will not start, contact your installer rather than power cycling repeatedly. Relay faults that persist after the documented stop and start procedure go to Tesla support via the installer.
Sleep StatePW3 · asleep, not deadDocumented Powerwall 3 behaviour rather than a fault. From software version 24.4, a Powerwall 3 enters Sleep when its enable switch is on but the system has been left stopped for more than 10 minutes. This is deliberate: it stops the unit draining its state of energy to 0%, at which point Tesla warns it cannot be recovered. Entering the wait, the logo LED flashes white once a second for 10 minutes; while asleep the logo LED is off, so the unit can look completely dead. It wakes every two hours on its own. If the system has been started it stays awake and resumes; otherwise it goes back to sleep after 10 minutes. The usual cause is a system left stopped after commissioning, service, or a fault shutdown. The fix is for the installer to start the system in Tesla One. It cannot be done from the owner app, so do not keep flipping breakers, and a unit that has sat stopped for a long period should be looked at promptly.
Alert not listed here?
Tesla adds alerts through firmware updates, and there is no published list to check them against — so send us what you can see. Most useful, in order: a screenshot of the banner before it clears (app alerts do not persist, and once it has gone nobody can recover the wording), a photo of the LED, the position of the side switch, and your serial number. Tell us the model too, because the LED means different things on a Powerwall 2, a Powerwall+ and a Powerwall 3.
Related Powerwall guides
Tesla Powerwall support hub
Hub · support · diagnosticsAll Powerwall problem guides, setup help, and diagnostic resources in one place.
See Tesla Powerwall support hubBackup · EPS · power cut
No backup during power cut
Why your battery did not kick in during an outage — transfer switch, SOC reserve, and Gateway checks.
See no backup during power cutTesla Gateway or app offline
App · Wi-Fi · Gateway · offlineTesla app not updating, Gateway offline, or power flow screen greyed out — the step-by-step Gateway guide.
See Tesla Gateway or app offlineTesla Powerwall fault questions
You cannot, and no honest table of them exists. Tesla has never published a Powerwall fault-code dictionary — not numbered, not lettered, nothing an owner or an independent engineer can look up. Any site showing you a tidy list of Powerwall codes has invented it. What Tesla actually gives you is two things: plain-English app alerts like “Powerwall Disabled” or “Breaker Open”, and the LED, whose meaning depends on which Powerwall you own — the tables above are Tesla's own, split by generation because they share nothing. Underneath, the Gateway does emit structured strings such as
PINV_a006_vfCheckUnderFrequency, but Tesla publishes no dictionary for those either; the only public list is a community reverse-engineering file in which most entries have no description at all. So the honest answer is: read the app banner, read the LED against the right table, and photograph both."Powerwall Disabled — Service Required" means an internal fault has been detected that prevents the unit from operating. Common causes include cell failure, a DC stage fault, or a ground fault during insulation self-testing. Turn off the enable switch on the side of the unit and contact your installer or Tesla support. This typically requires a site visit and may result in a warranty replacement — a power cycle will not fix it.
Two things worth knowing, and the second one matters. First, “green” is not Tesla's word — Tesla's Powerwall 2 LED table uses no colours at all, only patterns, and Powerwall 3 has no green state whatsoever. Second, and this is the part most pages get wrong: Tesla's current owner manual says a flashing Powerwall 2 LED means fault present. The “no communication with the Gateway” answer comes from Tesla's 2017 manual and has been superseded — it is still mirrored all over the web, and we printed it here ourselves until we rechecked it against Tesla's current documentation. If your Powerwall's LED is flashing, treat it as a fault rather than a broadband problem: check what the app says, photograph the LED, and get it diagnosed. Do not go looking for the Gateway's reset button — Tesla states the Gateway is not user-serviceable and warns against opening its deadfront cover.
STS offers remote diagnostic assessments from free. Powerwall systems log detailed data including charge cycles, temperature history, and alert logs. We review your Tesla app data and system configuration remotely to identify the root cause and advise whether you need a Tesla warranty claim, a Gateway reset, an electrical check, or a site visit. We are independent from Tesla and provide an unbiased assessment.
No. Tesla's Powerwall warranty (European Warranty Region, Rev 1.15) tells you to “contact the Tesla certified installer who sold you your Powerwall” — and then, explicitly, “if you are unable to contact the Tesla certified installer who sold you your Powerwall, or if you purchased your Powerwall directly from Tesla, you should contact Tesla”. That second route is the one nobody tells you about. Tesla lists powerwallsupport@tesla.com and +44 800 098 8064 for warranty claims; +44 1628 450630 is also in circulation as a Powerwall support line. An RMA number has to be obtained from Tesla before anything is returned. Three more things worth knowing: the warranty transfers — “a subsequent owner of the Powerwall who provides proof of ownership is also entitled to make Warranty claims”; a Powerwall that has never been online is still honoured “for at least four years following the date your Powerwall was installed for the first time”; and UK retention is 80% of rated capacity at ten years. One bright line to respect: the warranty excludes work “performed by anyone other than Tesla or a Tesla certified installer”, which is exactly why we diagnose and advise rather than opening the casing.
Powerwall 2 is an AC-coupled battery that pairs with a separate solar inverter. Powerwall 3 is a hybrid unit with a built-in solar inverter — it connects directly to PV panels as well as the battery. Powerwall 2 uses a Backup Gateway 2 for grid switching. Powerwall 3 uses a Backup Gateway 2 (the Backup Switch sold in some markets is not offered in the UK). It shows alerts through the Tesla app, but Powerwall 3 has additional fault types related to its integrated solar inverter — including arc fault detection and PV string monitoring.
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Service notice
We’re busier than ever. Thank you for your patience.
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.
Every message is read and answered, so please don’t send it twice; that only slows the queue.
Ronald Director, Solar Tech Support
On-site: Yorkshire only, for now
Remote: UK-wide, as usual
Remote fix: £125 if we fix it, no charge if we don’t
Replies: within 7 days
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