This isn’t a post being written about a fault or a diagnoses i’ve come across on a site, but rather just a summary of some of the more common fault codes you could ever receive from your Deye or Sunsynk inverter (i’ll do more like this on other inverter brands later down the line), what they really mean and how you can resolve them.
Many of the codes mean one thing in specific, but the real resolution to them could be one of many things, but understanding what the actual fault code you’ve been presented with is always the first step in to diagnosing its fix. I’m just pulling the codes from the user manual for this post as I would tend to assume these would be classed as the most common.
Deye / Sunsynk F08 Fault (GFDI _Relay_Failure) – This is not one i’ve come across yet, but from the user manual it notes that this is from a lack of a neutral-earth bond. This is a fault that would most likely only present itself when the inverter is running in off grid (anti islanded) as it shares the grid neutral when on grid (which is likely to be bonded on council side). This is a safety concern that when running in off grid mode, the ungrounded neutral will be a live conductor and earth leakages (RCDs) down stream from the inverter will not operate correctly. A fault like this should be attended to immediately by an electrician. The resolution would be to have a neutral earth bond created on the output of your inverter (local regulations here will apply).
Deye / Sunsynk F13 Fault (Working mode change) – I’ve only seen this fault when settings changes that typically would require a reboot on the inverter are done while the inverter is in normal operation. So if you’ve changed from “no battery” to “lithium” or vice versa (or to use battery V or %) this F13 occurs, i’ve seen it when changing parallel functions as well before and have also seen it when changing grid settings (mostly changing phase rotation to rid the W03 fault on a 50kW inverter). It shouldn’t really mean anything serious and the fault should clear itself after a minute or so after a setting change was made, if it doesnt just perform a reboot of the inverter by switching it power button, waiting a few seconds for the fault to clear then switch it back on again.
Deye / Sunsynk F18 Fault (AC over current fault
of hardware) – Another one i’ve never actually come across, but according to the user manual appears to be an overload of the backup output of the inverter. I would expect this to appear as just an “overload” event fault, but given that a typical overload can only really exist in off grid operation (anti islanding) it could likely be that this fault would present itself when it exceeds the inverters passthru current, the amount of current the inverter can support to its output while on grid (first need to understand that the inverters typical output of a 5kW inverter for example is indeed only 5kW in off grid operation, but can be around 10kW while in on grid operation as it can supplement its inverting capability from a grid supply). So if its passthru current is exceeded that when i most likely expect this fault to occur. The only real fix here, if you’re experiencing this regularly would be to reduce the load on the output of the inverter by moving some essential circuits to the non essential circuit loads, or to increase inverter capacity).
Deye / Sunsynk F20 Fault (DC over current fault of
the hardware) – This is again another one i’ve never come across before. The maunal seems to suggest it could likely originate from a bad DC connection either on PV panels or even from battery side resulting in what we call a DC ripple (although this typically would give over voltages rather than over currents) or more likely that your PV string current output exceeds the maximum of the inverters PV input. I would start by checking all DC connection points for any bad connections and also double check the output of your PV panels that they’re not exceeding the inverters max input current. It is also possible (although it presents itself as a different fault code), that the max discharge current of the battery is set to low for what the load is when running in off grid operation (if the load requires 5kW from the battery, this is 100A at 48v. If max discharge current is set only to 50A then the draw from the battery has exceeded what it’s allowed to).
Deye / Sunsynk F22 Fault (Tz_EmergStop_Fault) – I’m not entirely certain why this classifies as a common fault, it’s another one i’ve never really seen before as it would typically only occur from a remote stop function (something other than the inverter itself telling it to shut down). The inverter will remain in this state until whatever it was that did the remote shutdown tells it to wake up again. The manual does also seem to suggest it could be from the inverters parallel dip switches are set incorrectly, if you’re running less than 5 inverters in parallel the two dip switches in each unit need to be in off (0) position and if you’re running more than 7 units in parallel, the master inverters dip switches need to be in on position (1) and the remaining inverters dip switches need to be in off (0) position. I would imagine this applies to a setup of 9 single phase units running in a 3 phase configuration as well, I would set master on phase 1 to on (1) and the remaining 8 to off (0).
Deye / Sunsynk F23 Fault (AC leakage current is
transient over current) – This is one I have seen a few times before. This typically occurs when either a transient current or AC leakage is detected by the inverter. I’ve only seen this where poor system grounding is in place. I would start by checking the PV grounding and ensure you have adequate surge protection devices installed to prevent transient currents. This can be a bit of a difficult one to trace out, but by completely isolating each PV string on the inverter, completely isolating the AC connections and having only one input connected at a time will be a sure way to determine where your fault actually lies.