Inverter replaced, sollar generation odd

I've lurked here for a while and found it a useful resource. But now I need some help/advice.

I've had solar since 2022 and it's worked fine until July this year. I had a power cut on the 29th July which knocked the inverter out - completely dead. I contacted my installer and they replaced it on the 12th August.

Since then I've noticed that solar generation appears to be limited in some way. On sunny and the battery is full generation is limited to 4kW. When the battery is filling it goes above this value - I've seen it go up to 5.5kW. It also seems to be affected by consumption in the same way.

This doesn't seem to make sense to me as I don't think generation should be connected to consumption or export. It doesn't tally with what I've seen with the old inverter either.

Here's a graph from just before the old one died:

And here's one from after:

You see how the blue solar power seems to flatten for most of the day, at almost exactly 4kW.

Do you think there's something wrong with my inverter or settings or has the way solar generation is recorded changed?

Many thanks, Neil

neild I suspect your installer has configured a DNO export limit of 4kW which is why its topping out.

If you have Home Assistant you can see and change this yourself via givtcp. Otherwise will need your installer or givenergy support to correct it.

geoffreycoan Thanks for responding. I've just had confirmation that they're going to come back on the 19th to replace the inverter. I do have Home Assistant though, so I'll take a look.

neild In the second picture in particular, the battery seems to drop very quickly late afternoon. Looks like there should still be enough solar to cover consumption. Is this what you expect? (Perhaps you're exporting to the grid ?)

(If it's just a configuration issue, is it necessary to replace the inverter ?)

geoffreycoan I'm having trouble finding that setting in Home Assistant/givtcp, any change you could you give me a pointer to it?

DD I'm on Intelligent Octopus Flux, and it tends to drain the battery during the peek period.

Re configuration issue - yes, if I can find a config error and fix it then I'll cancel the replacement.

neild geoffreycoan I'm having trouble finding that setting in Home Assistant/givtcp, any change you could you give me a pointer to it?

the inverter export limit is sensor.givtcp_xxxx_export_limit - expressed in watts, so mine is 10000 for example

Does the label on the side say 3.6kW?

Rubikcube Does the label on the side say 3.6kW?

The label on the side doesn’t mean much, but it’s a good point. The installers may not have configured the inverter as being a 5kW inverter, it may be setup as a 3.6. It’s just a software configuration change that either your installer or givenergy can do, assuming you bought a 5kW originally. Your installer should be able to do it remotely as well

[unknown] Hmm, I've just looked at the model in the portal and it says it's "GIV-HY3.6". I'm assuming that this means it's unable to do any more than 3.6kW. I'm not actually sure what I had before, but I'm assuming that it was one that handled 5kW - so it looks like they might have replaced it with the wrong model. Does that sound right?

Aha! I've just found a photo that I took of the old inverter. It was a HY5.0 model! That explains the change in behaviour!

I've got 5.6kW worth of panels, so they've managed to replace it with the wrong one.

neild Presumably that's why they're coming back to replace it again?

Doh!

neild I've got 5.6kW worth of panels, so they've managed to replace it with the wrong one.

No, they haven’t replaced the inverter with the wrong one, they have misconfigured it, as per my point above.

I had my 5kWh hybrid replaced by givenergy under warranty when it failed. The engineer got the new inverter out of the box and I noticed it said 3.6kW on the side. Argh I said, trying to stop them downgrading me.

Not to worry said the engineer, the 5kW and 3.6kW are the same inverter internally, it’s just a software configuration change to limit the output. He then proceeded to peel the old 5kW label and stick on on the replacement inverter.
When he commissioned it he changed it to 5kW (I think it was the G100 setting?) and set it to my old inverter serial number so the portal was unaffected.

Your installer should be able to do this Neil, doesn’t need another inverter swap

Installers can't do it (I have an installer account and I'm not given any option to do this) the same way we can't change inverter serial numbers.

I know how it is done, but only Givenergy can officially do it. (And even then I'm not sure if they still do it these days)

*unless your installer has somehow managed to get hold of internal Givenergy software in which case I'd quite like to compare notes!

hoggy Installers can't do it (I have an installer account and I'm not given any option to do this) the same way we can't change inverter serial numbers.

I know how it is done, but only Givenergy can officially do it. (And even then I'm not sure if they still do it these days)

Ah, it was a GivEnergy engineer who did it as part of my warranty replacement, so they probably have higher level ability.

Thinking about it, I can understand why installers wouldn’t be given the ability to do this, they’d buy 3.6 inverters and magically upgrade them to 5kW.
Not being able to change the serial number is a pain though if your installer replaces the inverter, means they need to recommission the system and I think you’d loose all your old portal data as a result of getting a new inverter serial no

geoffreycoan DNO's would be EXCEPTIONALLY unhappy if installers/users could change the power rating.

They're pretty unhappy in general about firmware configurable power limits because as you can imagine there's a lot of ways around it and people are happy to pay - "boost your export etc". Its happened in other (more advanced) PV markets so it'll be happening here. NB - that relates to a lot more inverter resellers than GE.

[unknown] I was very disappointed to see my last 3 years' worth of data disappear when I got the new inverter. But the data doesn't actually get deleted, it's still available - but only through the givenergy APIs. I was able to download all my data and can visualise it in Excel - which is what I did with the graphs I showed in my first message. As long as you know your original serial number you can get the data.

I just thought I'd update you on the resolution to my issue. My installer switched out the Gen 1 3.6kW inverter for for a Gen 3 5kW inverter. So I'm very pleased - I understand that it charges and discharges the batteries quicker, which is great.