Odd event - Growatt SPH inverter

[David_1224]

Just opening this in the event that any other SPH inverter users on here may have seen anything like this before.
I've documented the system install in previous posts but since final sign-off in early Feb everything has run pretty much as expected.
HOWEVER
Evening of Thursday 16th May at 20:55 the system suddenly switched from drawing power from the battery to taking it from the grid despite the battery state of charge being in the mid 70s%. System is set to Load priority.
After about 40 mins it then switched back and resumed drawing from the battery.
Power consumption at the time was a few hundred watts and no high power devices were switched on/off and I have nothing about that's on a timer.
Obviously concerned as to what was behind this, so kept an eye out to see if it was the start of something a bit more serious. (newbie obsessive )
Suffice to say in the following days the system behaved as expected. Power drawn down from the battery overnight and no switches.
I also trawled back through previous months of data and couldn't spot anything similar having happened before.
So I was of a mind to believe the system may have had an update or ran a self check or something which took it off-line for awhile and that was it.
THAT IS UNTIL the following Thursday the 23rd when at 20:55 the system repeated the same sequence as the previous week.
The timing may just be a coincidence but I'm not generally a fan of those.

Anybody seen anything like this before?

If it does it again, particularly if its next Thursday , I'll run out to the garage and see if there's anything on the inverter display (Status!) that might give a clue.

Ether way I'll update the post.

 

[johnb2713]

Growatt SPH series of inverters have an annoying bug that happens around the time when Solar PV starts to generate and when Solar PV stops generating. Growatt claim the inverter is going through a self test and calibration routine, I say that's baloney but the net result is power is taken from grid despite having a good level of charge in the battery. You will see it happen just before sunrise and just after sunset dependent on cloud cover etc. Watch the voltage from you panels and you will see a level at which it starts this weird process.

 

[johnb2713]

Growatt SPH series of inverters have an annoying bug that happens around the time when Solar PV starts to generate and when Solar PV stops generating. Growatt claim the inverter is going through a self test and calibration routine, I say that's baloney but the net result is power is taken from grid despite having a good level of charge in the battery. You will see it happen just before sunrise and just after sunset dependent on cloud cover etc. Watch the voltage from you panels and you will see a level at which it starts this weird process.

I resolved the issue by fitting an additional inverter and battery, the inverter is a Victron Multiplus II and that happily takes over at the times when Growatt is testing and calibrating, Another inverter I looked at was SolarEdge, I'm glad I didn't go that route though, I have since learned that if you have a SolarEdge battery and inverter but no solar connected to it, their guarantee is void!

 

[David_1224]

Hi John,
Thanks for the replies.
I'm aware of the "calibration" routine as you and others have covered this in several other posts.
I can certainly see traces of this, particularly in the mornings, almost each and every day since commissioning, but they are of a relatively short duration.

What marked this out for attention was that this is a VERY distinct event in the records which first occurred on Thursday 16th and then repeated the following Thursday 23rd at exactly the same time and duration, +/- 5mins.
There are NO equivalent events on any other day going back over ALL the available data I can access, months, or between the two events.
What makes it stand out is that looking at the system power traces these fall to absolute zero for the duration of the event.
There are NO other times in the records, other than when the battery charge was depleted to minimum SOC, that this happens. (Which has not happened since we moved into spring and longer duration days)

Cut to last night and I checked at 20:55 and all was good
So was going to resign myself to it being a "coincidence" until I checked again this morning to find the event did happen but this time started at 21:25 and lasted 40mins.
So that's 3 consecutive Thursdays.

Yes it could be the "twilight" trigger but why suddenly starting now? apparently only on a Thursday? and a longer duration than anything else I've seen?
That's probably a rhetorical question as I posted simply to see if anyone else had ever noted anything similar to which it would seem not, other than the documented calibration routine.
or folk just don't spend that much time looking at data and have plenty of better things to do with their time

I just hate having a data set which does something I can't explain. (a lifelong affliction )

 

[binky]

Might be worth contacting the helpfesk to see if they have an explanation. Could be software updates, or a glitch.

 

[David_1224]

Well Thursday came around again and .................................... nothing.
As Binky says, looks like It'll be a glitch, though I'd expect it to be much more random and this was suspiciously regular (till last night), or a software update.
I'll lob a query to the helpdesk and will update if I hear back.
Don't hold your breath though this is likely to be where this post ends.

Just out of interest, and to other SPH users out there, the inverter firmware is showing as RA1.0
I'm pretty sure that's what it came with at installation but what does anybody else have?
Just interested.

 

[johnb2713]

Thats good news that you've only suffered a glitch, you can put your mind to rest