Solar & Electrical | Services & Systems

Growatt AC Coupled Battery Storage Inverter Support, Faults and Repairs

Established in 2011 in Shenzen, China, Growatt launched it's first products for the UK market in 2013. Growatt is now one of the top 4 solar inverter manufacturers in the world, operating in 180 countries. In 2021 Growatt became the world's largest residential solar inverter supplier. A widely installed Growatt AC coupled inverter is the Growatt SPA3000TL BL.

Growatt AC Coupled Battery Storage inverters are supplied with a 10 year manufacturers warranty so even if the initial installer is no longer trading then there is a good chance that if there is found to be a fault with the inverter that it can be repaired/replaced under the manufacturer's warranty.

Growatt AC Coupled Battery Storage inverters have an LCD display on the front of the chassis, which providing it's working, will highlight any errors with the inverter or the batteries that it runs. We have listed and described common faults with Growatt AC Coupled Battery Storage inverters and what action to take to resolve them below:

Growatt (Grid Tied) Solar Inverter Faults and Repairs

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How to Restart a Growatt AC Coupled Battery Storage Inverter:

Batteries: To restart a Growatt battery storage inverter start with the batteries. On the master battery there will be an on/off switch, switch this 'off'. If there's a circuit breaker, a fuse or an isolator installed between the batteries and the inverter also turn this 'off'.

AC/Mains/Grid Near the inverter there will be an AC isolator, this is used to isolate the mains/grid supply from the energy storage inverter and to prevent the inverter from feeding battery power into the electrical system. Switch the AC isolator 'off', if the inverter is running correctly you will hear a clunk inside the machine and after a while a 'no-grid', 'missing grid' warning or similar on the LCD display.

AC Isolator Pylontech US2000

When all of the lights on the inverter have gone out, reintroduce the batteries by turning the master battery 'On' and switching any installed fuses/circuit breakers/isolators installed between the batteries and the hybrid inverter 'On'. You should see the inverter recognise the batteries on the LCD display which providing the batteries are charged will light up. Batteries from Pylontech and others sometimes also have a start button. To startup these batteries you may also need to press and hold the start button for (3-5 seconds). On the Pylontech batteries the start button is the inset red button marked 'SW'. If successful, you'll see the green 'SOC' lights illuminate showing you the state of charge of the batteries. When more than one battery is present the master battery will be the one with the communications cable connected. Turning on the power to the master will turn on all the others in the stack. Introduce the AC/mains power supply by turning the AC isolator 'on'. This will restart the energy storage inverter, on the display it might show you progress during it's startup procedure. During startup is when the inverter carries out all of the tests needed before being able to connect the batteries to the electrical system. If errors are found during testing they will be displayed on the screen or an indication light might come on. Make a note of any warning messages, warning lights and fault codes.

Growatt AC Coupled Battery Storage Inverter Fault Codes and Explanations:

• AC F Outrange - The inverter is measuring a grid (mains) frequency that is either too high or too low in relation to the parameters that the inverter has been set to safely operate within. If this fault persists and mains power is available to other local circuits then check that all isolators, MCBs and RCDs on the AC side of the solar PV system are 'On'. If automatic safety devices such as MCBs or RCDs have switched 'Off' then leave them 'Off' and contact us to arrange for a solar engineer to visit to establish whether the fault lies with the inverter, the supply circuit or with the grid.


• AC V Outrange - The inverter is measuring a grid (mains) voltage or a grid impedance that is either too high or too low in relation to the parameters that the inverter has been set to safely operate within. If this fault persists and mains power is available to other local circuits then check that all isolators, MCBs and RCDs on the AC side of the solar PV system are 'On'. If automatic safety devices such as MCBs or RCDs have switched 'Off' then leave them 'Off' and contact us to arrange for a solar engineer to visit to establish whether the fault lies with the inverter, the supply circuit or with the grid.


• Battery Open - The inverter is not electrically connected to the battery/batteries. Ensure that the batteries are switched on and that any switch fuses / DC isolators installed between them are switched 'On'. If the batteries and any DC fuses are 'On', you suspect that a DC fuse might have blown and or there is no power in the batteries, contact us to discuss the next steps.


• BAT NTC Open - This error code applies to systems using lead acid batteries with a battery temperature sensor connected to the inverter. The inverter has lost communications with the sensor. Ensure that the sensor is well installed and restart the inverter. Contact us if this error code either isn't applicable and or it doesn't clear after a restart.


• Battery Reversed - The inverter understands that the positive and negative terminals to the batteries have been reversed. Check both ends of the cables between the batteries and the inverter including the terminals in any switch fuses/ DC isolators and ensure that the polarity is correct. Contact us and or email us a picture of the setup, if we can help with this.


• Bat Voltage High - Battery Voltage over 60V - The inverter is measuring a DC voltage from the batteries over 60V. Turn off the batteries and isolate them via any fuses/DC isolators installed between the batteries and the inverter. Ensure that all connections are secure. If you are comfortable and have the tools to do so, measure the voltage at the battery terminals and ensure that it's within range. If the battery voltage is over 60V, leave the batteries disconnected from the inverter to avoid damaging it. If everything is ok, restart the inverter. If the error persists and or the battery voltage is higher than expected, contact us to discuss the next steps.


• Bat Voltage Low - Battery Voltage under 42V - The inverter is measuring a DC voltage from the batteries under 42V. Turn off the batteries and isolate them via any fuses/DC isolators installed between the batteries and the inverter. Ensure that all connections are secure. If you are comfortable and have the tools to do so, measure the voltage at the battery terminals and ensure that it's within range. If the battery voltage is under 42V, restart the inverter and try and use the inverter to force charge them using the mains/AC supply. If the error persists, if the battery voltage remains low and or if they won't power up, contact us to discuss the next steps.


• BMS COM Fault - Communication fault - The inverter has lost communications with the batteries. Check that the batteries are powered on and that the communications cable is securely connected at both ends. If the batteries are powered on and the communications cable is secure, contact us to discuss the next steps.


• BMS Error: XXX - The inverter has picked up on a Battery Management System (BMS) error that has been generated from the batteries. The battery is signalling to the inverter that there is a battery problem. Check the status of the batteries including checking the battery manual. Restart the batteries and the inverter. If the error persists, contact us to discuss the next steps.


• BMS Warning: XXX - The inverter has picked up on a Battery Management System (BMS) warning that has been generated from the batteries. The battery is signalling to the inverter that there is a battery problem. Check the status of the batteries including checking the battery manual. Restart the batteries and the inverter. If the error persists, contact us to discuss the next steps.


• EPS Volt Low - The inverter may have detected a load on the Emergency Power Supply (EPS) circuit that is too high. Check that the loads on the EPS circuit are within range, paying particular attention to appliances such as pumps, motors and anything else that may require a high inrush current to startup. If the EPS loads are within range or if the EPS mode is not in use and this error persists, contact us to discuss the next steps.


• Error 120 - Model set up does not meet with certification - Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems, this is most likely an internal problem with the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 121 - This is an internal inverter communications fault between the master and slave processors. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 122 - Bus Voltage Fault - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 303 - The inverter has picked up on a problem with the mains AC power supply. If this is a new installation check that the L & N conductors are installed in the correct terminals. If an existing installation, shutdown the system, isolate the AC circuit and ensure that all conductors including the earth/CPC are in good condition, check terminations in isolators, MCBs and meters along the length of the circuit. If everything is ok and after the system has been safely restarted, this condition persists then contact us.


• Error 405 - Relay Fault - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 406 - Model set up does not meet with certification - Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems, this is most likely an internal problem with the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 407 - Auto Test Failed - The inverter has recognised a problem (which may be temporary) upon initialisation at startup. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 408 - The inverter is too hot. This could be due to a number of factors, for example 1) If the inverter is exposed to direct sunlight 2) If the inverter has been installed without adequate ventilation around the chassis which would allow excess heat to dissipate 3) The inverters components are getting too hot due to an internal component fault. If the unit isn't running hot and if after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 411 - Internal Communications Failed - This is an internal inverter communications fault between the master and slave processors. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 417 - Sample Fault - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• Error 418 - DSP and COM firmware version mismatched, system fault - Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems, this is most likely an internal problem with the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• No AC connection - The inverter is not measuring a grid (mains) voltage suggesting that mains power to the unit has been disconnected. If this fault persists and mains power is available to other local circuits then check that all isolators, MCBs and RCDs on the AC side of the solar PV system are 'On'. If automatic safety devices such as MCBs or RCDs have switched 'Off' then leave them 'Off' and contact us to arrange for a solar engineer to visit to establish whether the fault lies with the inverter, the supply circuit or with the grid.


• NTC Open - This is an internal error within the inverter. If after the system has been safely shutdown and restarted this condition persists then contact us.


• OP Short Fault - EPS Output Short Fault - The inverter has picked up a problem (a short circuit) with the loads on the Emergency Power Supply (EPS) circuit. Isolate the EPS circuit from the inverter and electrically test the individual circuit(s) being supplied via the EPS. Only reconnect and restart the inverter when satisfied that the circuits being supplied by the EPS are in good condition and operating correctly. Contact us if we can help with this.


• Output High DCI - The inverter is measuring too much DC current (I) from the batteries on the grid side. Assuming that this is an existing installation that has been specified correctly, hasn't recently been changed or added to and has operated before without problems. This could mean either a problem with the batteries or with the inverter. Restart the inverter. If the problem persists, we would advise that the DC side of the system is disconnected using the DC Isolator installed between the batteries and the inverter (if available) and or by switching 'Off' the batteries at the battery/batteries. Contact us to test the DC side of the system including and excluding the inverter.


• Over Load - EPS Output Overload - The inverter has detected a load on the Emergency Power Supply (EPS) circuit that is too high three times in a row and has shutdown the EPS circuit for an hour. Check that the loads on the EPC circuit are within range, paying particular attention to appliances such as pumps, motors and anything else that may require a high inrush current to startup. If the EPS loads are within range or if the EPS mode is not in use and this error persists, contact us to discuss the next steps.


• Pairing Time Out - Communication fault - The inverter has lost commuications with a CT clamp. Check the cabling and make sure that the CT clamp(s) are properly closed and secure. Remove and reattach the CT clamp(s) and restart the inverter. If the warning persists, contact us to discuss the next steps.


• Warning 401 - SP-CT/Meter Communication fault - The inverter has lost commuications with either a CT clamp or an external meter. Check the cabling and make sure that the CT clamp(s) are properly closed and secure. Remove and reattach the CT clamp(s) and restart the inverter. If the warning persists, contact us to discuss the next steps.


• Warning 506 - Battery temperature out of specified range for charging or discharging - The inverter is measuring an external temperature that is either too hot or too cold for the batteries. Check the external temperature is within the range that the batteries can operate. If the external operating temperature is within range for the batteries and this warning persists, contact us to discuss the next steps.

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Growatt AC Coupled Inverter Manual

Growatt SPA1000-3000TL Operation Manual

Solar Battery Repair and Recovery

If you find that your lithium solar batteries have over discharged and refuse to power up, have developed a fault, won't hold their charge and or if you find them completely dead, we may be able to help you to recover them. If a component has failed we may also be able to source the parts needed to repair the unit and get it back into service.

In the first instance contact us a let us know more about the faulty battery and your system, either over the phone or by email, pictures are always useful and appreciated. We can then decide the best way to proceed, we have portable equipment that enables us to charge lithium batteries on-site, we also have workshop facilities here in Swindon that can be used.

If the batteries are still within their warranty period we can also take care of any testing/installation work and liase with the manufacturer on your behalf to prove the fault and process a warranty claim.

Solar Inverter Recycling: - Recycling Growatt Inverters

Growatt energy storage inverters contain valuable materials such as copper and aluminium, these materials are in high demand and recycling them is significantly less energy intensive than extracting them from ore.

If you find yourself with a damaged or faulty Growatt storage inverter, we will be pleased to help you recycle it.

• There is no charge for this service but all costs involved with decommissioning and transportation are covered by you.
• If you're delivering an inverter to us in person, although it's usually no trouble to arrange other days, the most convenient time for us is between 9am and 2pm on a Saturday, please let us know of your visit with an approximate time in advance.
• We do not buy or sell used solar inverters or used inverter parts. For UK buyers and sellers, we've found ebay to be the best place for buying used solar inverters and inverter parts.
• We can accept deliveries by courier at all times throughout the week but please contact us before you arrange this.
• We can also help to recycle solar panels, solar batteries and solar mounting equipment.

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Solar Power System Testing, Servicing & Maintenance

Regular solar PV system testing, servicing and maintenance will extend the life of a solar PV system and ensure that solar panels are always operating safely and at their best, whilst maximising yields.

We offer complete safety and performance testing for solar PV power systems of any size. Includes solar panels, cables, solar inverters, isolators and mains connections. We provide solar power system testing and maintenance services for residential, commercial, industrial and agricultural clients across Southern, South West England and the West Midlands, with specialist experience working with farmers, developers and commercial and industrial buildings owners.

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Solar PV Inverter Replacement

If you have a faulty solar inverter, we offer an efficient, value for money, hassle free solar inverter replacement service. We offer good advice and install quality equipment with comprehensive warranty and support options. We will test the rest of the system as part of the service, take care of all hardware deliveries, record the new unit's serial number and confirm the warranty details with the manufacturer.

Our solar electricians work cleanly and will dispose of any unwanted boxes, faulty equipment and packaging. Many modern solar inverters can now use wireless home networks to transmit solar generation data to PCs, tablets and smartphones, so if you would like something like this, let us know and we will be happy to set it up as part of the installation.

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Grid-tie inverters, Hybrid Inverters, AC Coupled Inverters, Battery Storage Inverters, Off-Grid Inverters, Charge Controllers, Transfer Switches, Hot Water Controllers, Optimisers, Lithium Batteries, Lead Acid Batteries, Solar Panels, Mounting Systems, Test Equipment, Earthing Equipment, Electrical Distribution Equipment, Cable and Accessories

Deliveries to anywhere in the UK are quick, tracked and accurate, technical support (by phone and on site if needed) and design/product advice is available before, during and after installation. The recording and collating of serial numbers, factory and other test results, manuals any other information required for equipment warranties, add ons and extensions is included. Trade, DIY and Retail Clients Welcome.

Bespoke system design, equipment testing and integration support as well as on-site technical support and job/equipment specific training is available for off-grid, hybrid, larger and or more complex systems.

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Mains/Grid Isolation and Surge Protection

A whole house surge protector is installed to provide protection from transient overvoltages originating from the mains/grid. A whole house surge protector is installed directly inline and as close as possible to the incoming mains/grid supply meter, this allows for surge protection for all circuits and equipment including solar inverters, routers, stereos and other sensitive electrical equipment within the network. The addition of a 100Amp lockable isolator also allows for safe and convenient isolation of all electrical equipment within the network including consumer units, solar inverters, battery storage units and EV chargers from the mains/grid in one place. Surge protectors are in compliance with the recently updated 18th edition amendment 2 of BS7671.

Mains/Grid Isolation and Surge Protection

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Articles: Further Information, Calculators & Solar Inverter Fault Codes

Lots of articles, calculators and technical information including links for further reading. Covering a range of topics related to the installation and maintenance of solar photovoltaic and electrical systems in the UK.

Growatt Inverter Faults and Repairs Established in 2011 in Shenzen, China, Growatt launched it's first products for the UK market in 2013. Growatt is now one of the top 4 solar inverter manufacturers in the world. The MTL-S Series solar inverters were widely installed in the UK from 2013 through to 2019. BSI - PAS 63100:2024 - Protection Against Fire of Battery Energy Storage Systems for use in Dwellings This Publically Available Specification (PAS) from the British Standards Institution (BSI) was sponsored by The Department for Energy Security and Net Zero. Although not yet a British Standard, this guidance was developed in response to an urgent demand for clarity as to good practice across the industry including product, service and process standards. How to provide backup power to a house using a portable generator In this article we show you how to provide backup power to your home using a portable diesel, petrol or LPG backup generator. We look at changeover switches, the importance of earthing, backup generator loadings, how to isolate non essential loads. We ask where to locate the backup generator when it's in operation, how best to safely isolate the grid/mains power supply and switch to a backup generator supply. Ground Faults, Isolation (ISO) Faults, RISO Faults and Insulation Resistance Faults with Solar PV Systems After a number of years exposed to wind, rain, snow, ice and sometimes animals; solar panel systems can start to develop faults. The most common faults we find related to exposure are ground faults, isolation (ISO) faults, RISO low faults and insulation resistance faults. In this article we take a look at what these faults are, the possible causes and what steps are taken to identify and resolve them.

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What Our Customers Say:

"Contacted Glen after being let down by 2 companies. He visited promptly, researched my system and assisted me with getting my solar system up and running again. Amazing man. Will definitely be my first and only port of call for any future issues. Friendly, supportive, knowledgeable and reliable. Highly recommend him." Margaret Bissett, Chisledon

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We've carried out Solar PV System design, installation, testing, repair and maintenance work on solar PV systems of all shapes and sizes all across the UK.

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We are located in Wanborough, very close to Swindon in Wiltshire, Southern England, UK. From here we service clients within a 90 minute driving radius including the towns, cities and regions below:

Swindon: Abingdon, Aldbourne, Amesbury, Andover, Banbury, Basingstoke, Bath, Berkshire, Bicester, Blunsdon, Box, Bracknell, Bradford on Avon, Bridgwater, Bristol, Buckingham, Burford, Burnham on Sea, Calne, Camberley, Cardiff, Carterton, Cheltenham, Chippenham, Chipping Norton, Chipping Sodbury, Cirencester, Corsham, Cricklade, Devizes, Didcot, Evesham, Eynsham, Faringdon, Frome, Fleet, Glastonbury, Gloucester, Gloucestershire, Hampshire, Henley-on-Thames, Highclere, Highworth, Hook, Hungerford, Keynsham, Kingsclere, Lambourn, Lechlade, Ledbury, Ludgershall, Lyneham, Maidenhead, Malmesbury, Marlborough, Marshfield, Melksham, Minety, Newbury, Newport, Oxford, Oxfordshire, Pewsey, Purton, Ramsbury, Reading, Ross on Wye, Royal Wootton Bassett, Salisbury, Shaftesbury, Shalbourne, Slough, Southampton, Stow, Stratford upon Avon, Stroud, Swindon, Tewkesbury, Thatcham, Tidworth, Trowbridge, Wanborough, Wantage, Warminster, Weston Super Mare, Wiltshire, Winchester, Windsor, Witney, Wokingham, Worcester, Wroughton and Yate.

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