AIO “too full” in Island Mode

Another unexpected, edge-case behaviour with my AIO today. Not seen this reported on this forum before.

A contractor working for the local DNO was replacing cables and telegraph poles in the vicinity, so we were informed of a planned interruption ie no grid connection from 0900-1700 today. I charged the AIO overnight as it wasn’t clear how much solar generation we would have throughout the day.

Power went off at about 1030. AII in One (AIO) went into island mode flawlessly - no interruption to our supply inside the house.

Until about 1200, when all power would go off for 1 second every 1 minute. Nothing tripped on the CU.

Was unable to access devices as no WiFi etc. as that takes longer than a minute to reset and establish the connection.

My hypothesis was that because it was sunnier than expected, and the house load was low, the inverter (GE gen 3 hybrid) was delivering power that the AIO couldn’t store because it was full, and couldn’t export because there was no grid.

I turner off the DC and AC inverter switches to test this, and it immediately stopped the resetting/ cycling of the house load - problem solved.

No errors reported that I can see on my AIO dashboard pages. No notifications of the issue that I could see.

One for you to add to the list perhaps @TheDragon (GivEnergy) - I think the AIO should be able to handle this more elegantly, or at least warn people that they need to isolate their inverter once their AIO is full, ie the inverter is generating power that has nowhere to go…

26Left
This is very interesting.

Not least because it was recently discussed here by @hoggy whose view was that the AIO would increase the frequency delivered to shut down the inverter and prevent this sort of thing.

It's should freq jump to stop that from happening. However equally (& seemingly undocumented on the datasheets) is that if the PV inverter can generate more than 32A it can cause the AIO to fault (which kind of sounds like what your getting)
So how big is your other PV inverter?

Found it, turns out it's lower BUT it should have rebooted in 54hz mode not got stuck in a loop?

max 5kw.
If you have more PV than the system can handle off Grid, the voltage spikes and the over voltage system shuts the system down.
Thankfully it will restart itself after 30s, at 54Hz. The PV Should then not be re energised. But with such a large array PV on and in Island mode isnt feasable, unless you leep the load high enough not to over volt the system

With 5kw, the PV can be absorbed by the battery to SOC 90%, where th frequency begins to moulate upwards, slowing or killing the PV at 90%SOC.

Opposite at 80%.

hoggy I have a 5kW GE gen 3 - will look at the inverter logs to see if there’s any evidence of 54Hz.

Hmmm. I have a 6kW Growatt inverter.

No evidence of it sending 54hz that I can see - BUT when the issue happens we don’t have data because the router was rebooting constantly like everything else…

This is the AIO grid frequency showing a supply interruption

This is the GE inverter “grid” frequency which is what the AIO was producing during the grid outage.

Here’s the log entry for the inverter

Anywhere else I can look to find a culprit?

Then only other anomaly of note that I can see is the AIO system data logging frequency. It usually updates every 5 minutes, but appears to hit an alarmed state of sampling every 10 seconds when the battery was full and PV gen > house load.

Interesting. Can you email in a serial number.

This frequency shifting should kick in at 90% SoC. So shouldn't get to 100% in island mode.

TheDragon (GivEnergy)
Paul - if you want another (much dirtier) data point I had an unscheduled DNO supply interrupt last Thu 18th at approx 1.13pm. SoC was 100% at the time.

Supply was blown for the entire region by an underground HV cable fault. I was away on holiday, but as far as I can tell from my logs my supply cut was actually very short even though the event lasted several hours for some neighbours.

My data collection was also poor, because my RCBOs all tripped, taking down at least some of my network. But maybe you can tell something from the AIO logs?

I think you have my serial number from the beta trials?

EDIT - oh, I also had a momentary power cut during a storm on the 17th at approx 6.37pm. The RCBOs did not trip for this one. The SoC was approx 98%.

(These are actually the only power interruptions I have had since install!)

TheDragon (GivEnergy)

Thank you for investigating. Email sent.

TheDragon (GivEnergy)

One extra thought.

The AIO was already at 95% when the grid dropped out at approx 0945

So is it possible that the “trigger 54Hz logic” only occurs if in island mode when passing through the 90% threshold?

Whereas in this case the 90% threshold was passed while in grid mode, and the AIO entered island mode at >90%, therefore never triggering the 54Hz frequency shift to knock my GE gen 3 hybrid 5kW inverter offline?

If so, can I suggest that is a bug, and that on the event of entering island mode, a check needs to be performed “if AIO soc > 90%, frequency shift”

Will this situation have damaged my AIO batteries due to overcharge?

26Left ok. sorry for the delay, Ive been away at stratigic lunch and meet and greet.

Now off to London

But MicroGrid Mode was turned Off. So Ive set it on, now need to expose this super engineer level register in the portal to check others, if this crops up again.

Register 332 if you ever needed to know

TheDragon (GivEnergy)

Thank you!

hoggy max 5kw.
If you have more PV than the system can handle off Grid, the voltage spikes and the over voltage system shuts the system down.
Thankfully it will restart itself after 30s, at 54Hz. The PV Should then not be re energised. But with such a large array PV on and in Island mode isnt feasable, unless you leep the load high enough not to over volt the system

With 5kw, the PV can be absorbed by the battery to SOC 90%, where th frequency begins to moulate upwards, slowing or killing the PV at 90%SOC.

Opposite at 80%.

Resurrecting this thread as this is the behaviour I have experienced recently. AIO SOC at 100% and plenty of solar from the Hybrid Gen 3 inverter. When grid was lost, the system shut down for 20-30 seconds (long enough to reset the router) then came back on with the frequency set to 54Hz and no solar.

I don't know whether it is technically feasible or not to "control" the inverter such that the inverter only supplies enough power to support the house load (maybe a little less so the battery provides some as well) as this would allow the battery to remain full whilst the sun is shining so that you would have a full battery once the sun has gone done (rather than currently where the solar is switched off until the SOC has dropped to 80%?)

Does anyone have any thoughts about this?