Solar PV 2 engineers gave conflicting diagnosis (SMA sunny boy)

QrizB

Looking at those photos, I wonder f you have the same problem that @kaysdee had back in May in this thread. Your display is showing the same feature; a gap in the "AC" side of the system, where there's meant to be a switch shown:

Here's a sceenshot from The Internet. You can see the "closed switch" that's missing from your photos.

It's a shame that kaysdee hasn't been back to update on how they fixed their system.

There are a few Sunny Boy owners on the forum; can any of those provide insight here?

Edit to add: @greyteam1959 had something similar in 2022, see this thread. I think they replaced their inverter?

QrizB

Also - are any of the LEDs to the right of the screen illuminating?

jimjames

We had a Sunny Boy inverter installed in 2011. It lasted until 2023 when it failed, sounds similar but with the cost of a replacement it wasn't worth trying to get the old one repaired especially when every day is costing money at 76p per kWh! Shame you've missed one of the best summers for sun.

gefnew

RED Electrical – Talk to a tradesman… not a salesman!

They have online guidance about fault finding errors etc.

Heedtheadvice

I find what you have written about the engineers reports/ actions confusing.

Given both engineers originally reported very low PV panel output voltage then I would agree with Qrizb's initial response ( assuming they measured during good solar light).

The fact that the second engineer did some work on the AC side ( who knows what!) might explain the graphic showing an open circuit switch ( I assume that indictates no AC power connection). Also eng 2 second statement regarding PV voltage is at odds with the initial report - is it 2.4v or 285v? [Edit: typo corrected ]

I would still suspect eng one and Qrizb first response to be the area worth checking. I helped out another poster recently and it was the same issue with a bad connection on a panel plug/socket. Unless scaffolding involved easy to diagnose/test and if the problem cheap to rectify.

The overall panel string can be tested prior to the DC switch ( with it isolated), the DC switch tested itself and the DC output then checked at the inverter connection off load and then under inverter load. That is half your system checked quickly and easily.

If the first check ( total panel output prior to DC switch,) shows a problem up then it is a case of checking each panel and it's connectors.

I suggest getting eng 1 to come back and take their diagnosis further in the first instance. Connectors are very cheap and equivalent panels ( if on is faulty ) can often be purchased used/surplus thus not affecting FIT .......which at 78p per kWh generated which you can also get benefit from ( maybe then worth up to £1 per kWh) is certainly very valuable as will SEG payment after FIT finishes.

Lablovezel

I decided to buy a new inverter. Needed to be replaced anyway. All working now. Thank you for the replies.

Heedtheadvice

Grand!

NoNote that you need to update your FIT supplier of a change ( maybe not same inverter but) like for like functionality. FIT payment is on the basis that the declared system has not changed but changes for fault repair, provided performance has not been changed is allowed. If performance has been increased payment kev is reduced pro-rata. ( I think that is still the case and someone who knows definitively will no doubt be along soon with details )