Solar and battery fault codes by brand
Find your manufacturer below, then your code. One thing before you start: switching off the inverter does not make the panels safe. They generate whenever it is light, and the wiring between them stays live.
Brands
Pick your manufacturer to see every code we cover.
Most looked-up solar or battery system codes
Across every brand in this category.
- Inverter shutting down in the middle of the dayAll brandsUsually the grid rather than your system. Inverters must disconnect when mains voltage goes outside the G98 protection settings, and exporting solar is what pushes it there.Usually simple to fix
- Generating less than expectedAll brandsThe rated figure is a laboratory number a British afternoon rarely supplies. Two published non-faults explain most of the rest: darkness and export limits.Usually simple to fix
- Battery not dischargingAll brandsBefore treating it as a fault, check what your tariff is asking. A battery holding charge in the evening is very often following a schedule correctly.Get it checked
- Panels are still liveAll brandsThere is no switch that stops a panel generating. Turning the inverter off makes it safe to stand next to and leaves the roof wiring live at hundreds of volts.Stop — call an engineer
- Flashing redTesla PowerwallTesla publish this as an inverter fault on the Powerwall 3. The other states matter more: an unlit expansion unit is normal, so is flashing white, and a Powerwall 2 uses a different table altogether.Get it checked
- 3501SMAInsulation resistance too low. SMA are unusually direct: the error is not caused by the inverter, it is in the DC installation — and it can come and go with the weather.Stop — call an engineer
- Inverter not connecting to the gridSMASMA disable the grid connection deliberately when a pre-start check fails. The event number in the Results menu is what tells you which check.Get it checked
- Grid OutageTesla PowerwallNot a fault on a system with a Backup Gateway. Tesla publish the notification text and the behaviour, including that the Powerwall may discharge below your reserve. A Non-Backup Powerwall 3 does none of this.Usually simple to fix
- 3701SMAResidual current. Unlike the insulation event this one trips a running system, and SMA publish the threshold: a sudden jump of 30 milliamps or more.Stop — call an engineer
- Breaker OpenTesla PowerwallA named app alert meaning the Powerwall’s AC breaker is off. Tesla say switch it back on — unless there is any sign of burning at the distribution board, when you stop and call them.Get it checked
Symptoms
No code on the display? Start from what it is doing.
Home battery not charging or discharging
A battery that sits idle is usually obeying a tariff, a schedule or a reserve setting, so read what it has been told to do before treating it as broken.Solar panels not generating
Establish whether the inverter is off, disconnected or simply producing less than you expected, because those are three different problems and only one of them is a fault.
How solar and battery fault codes work
Start with the hazard, because this is the one category on this site where the usual instinct is actively wrong.
A solar array is a generator you cannot switch off. Isolating the alternating-current side makes the inverter safe to stand next to and leaves the direct-current side — the panels and the wiring between them — live at several hundred volts for as long as there is daylight. There is no switch that stops a panel generating. Every other appliance we cover can be made safe by an owner in a few seconds, and this one cannot, so "turn it off first" is not sufficient advice here and we will not give it. Anything on the DC side belongs to a qualified person, and that includes work you might reasonably think of as trivial.
With that said, a great deal of what these systems report is not a fault, and the biggest group has nothing to do with your equipment at all. Grid-related shutdowns are the commonest thing a UK inverter reports, and the usual cause is mains voltage. An inverter is required to disconnect if the grid voltage goes outside a permitted band, and it exports by pushing its voltage slightly above the grid's — so on a bright day in a street where several houses are exporting, the local voltage rises and inverters start dropping out. Nothing is broken. Your system is doing what the regulations require. If it happens repeatedly at midday in summer, that is a distribution network issue worth reporting to your network operator rather than a repair to book.
The genuinely serious faults are worth naming so you can tell them apart. Isolation and insulation resistance faults mean current is finding a path it should not, and they often follow rain or a rodent finding the cabling. Arc faults mean the system has detected the signature of an electrical arc, which is a fire risk and is the reason the detection exists. Neither of these should be repeatedly reset to make it go away.
On the battery side, the two common reports are state-of-charge behaviour and communication between the battery management system and the inverter. Before treating either as a fault, check what your tariff is asking the system to do. A battery that sits at a fixed charge and refuses to discharge in the evening is very often following an off-peak schedule correctly, and a system exporting nothing on a sunny afternoon may simply be export-limited, which is a setting rather than a failure.
Two more non-faults worth ruling out. An inverter shutting down at dusk and staying dark overnight is normal, not a failure to restart. And a system generating far less than its rated output is usually reporting the weather rather than a fault — a peak figure is measured under test conditions that a British afternoon rarely supplies.
The legal position, accurately: this is notifiable electrical work under Part P of the Building Regulations in England and Wales, and installation is normally done by an electrician registered with a competent person scheme, with most domestic systems installed under MCS. What that means practically is that the useful call is to your installer rather than to the panel manufacturer, and that a fault which keeps returning after a reset is one to escalate rather than to keep clearing.