3.6kw Inverter tripping electrics when inverter wakes from low power mode
TLDR: Long story short, ever since the low power mode software update my inverter has been tripping the electrics when it wakes up in the morning. Installer is a bit of a loss and wants to just take it off all RCD/RCBO to make the problem go away. Sounds a bit risky to me.
I have the following equipment which has been installed since Jan and basically working fine:
-3.6kw Ecco inverter SW Ver.M 2.3.8.3 / S 1.5.1.5 / C E.4.2.9
-5.1kwh SunSynk battery
-6kw array 15x400W panels
After the low power mode software update in Feb, the inverter has been tripping my fuse/rcd/rcbo intermitently first thing in a morning when it comes back to life. I can't seem to narrow down a pattern for when it will do it or not. It will be fine a couple of days, then it will trip every morning for 5 days straight then it will be ok again.
It's not the end of the world as the solar just goes into the battery until I wake up and flip the switch again, then it start working as expected (until the next day).
A bit of history.
Originally, the installer put the inverter on a shared RCD. This was a 30mA RCD shared with a few other things such as my cooker and some sockets down stairs. This was annoying as I had to keep resetting my cooker clock. I have been told on some youtube comments on the SunSynk channel that his was very dangerous and inverters should never share an RCD as this is against UK code. Quite surprised and bit annoyed by this to be honest. Why didn't installers know this?
Anyway, they came out and swapped it onto its own B32 RCBO switch/Fuse away from the shared RCD. The exact same behaviour is seen. It will work some days and other days it will trip so I need to flick it in the morning.
Now they're talking about taking it off a fuse/rcd altogether. They say it doesn't need to be on one. That sounds a bit suss to me. What do you think?
I logged a case with SunSynk ages ago which got escalated to the inverter manufacturer in China. They said they are working on a software fix for this which sounds promising but it's been about 2 months now and every time I email them they just say it's "coming soon". Others have experienced this same problem with the low power mode so it seems to me like it might be a software issue but I don't know why everyone isn't getting it if it really is.
Someone in the YouTube comments said they had a similar issue when their neutral wire was not tightened into the consumer unit correctly which was causing a small arc sometimes and tripping it. This sounds promising but what are the odds that the installer got this wrong the first time when putting it in its own fuse in the shared RCD and then again when they moved it onto it's own RCBO?
Here is an example of what it looks like on the charts when it trips
And here is an example of the chart on a day when it didn't trip.
I wonder if something about that large vertical power draw from the battery could be doing it. You see on the day it doesn't trip the ramp up is much more gentle.
Anyone got any ideas?
The installer is talking about removing in Inverter from the RCBO/RCD all together. I'm not sure how happy I am about this. Apparently according to him it doesn't really "need" to be on one at all. I'm not sure if that is really true or up to code. Anyone got any idea if that's true?
The manufactures of the inverter got back in touch and said they cannot reproduce it. Not sure if that is true either as earlier on they said they could and were looking into it. Also the fact that others are having similar issues suggests there is a problem. I hate the idea of papering over the cracks rather than actually getting to the bottom of it.