I am a new PV householder - advice please. Unbalanced strings and wrong inverter

[whinmoor]

If you'd like some photos posting, email to me and I'll try to put them up: [email protected]

 

[juniperz]

Hopefully you havn't had to pay a deposit so will have the upper hand.

I have paid 20% deposit...

 

[juniperz]

Whereabouts in the country are you?

Bristol

 

[juniperz]

(5th post)

- - - Updated - - -

(6th post

 

[juniperz]

When I contacted Growatt, their Tech Support person said:
"Max. number of parallel strings, means that you could connect 2 strings per MPP tracker. This is usefull when working with low power modules.

This particular inverter can work with the panels STP245S-20/Wd with an string between 5 and 8 panels, so 8+8 will work fine. If you 12+4 you are overloading one of the MPPT trackers (see screen shoots ).
Unless both roof are at facing the same azimuth and with the same tilt, you could physical split them 12 +4 but electrical 8+8.

Here's the 8+8 config

And the 12+4

 

[whinmoor]

 

[juniperz]

Thanks whinmoor - I decided to get to 6 posts! The post above shows the connections and the front of the inverter

 

[juniperz]

Although I would reject the system on the basis of the inverter, is it not possible that the installer has wired four of the roof panels with the four garage panels on one string, then the other eight roof panels on a second string?

I guess that is possible, but if that is the case, then his annotation on the junction boxes is misleading.

I can trace the wires actually - 1 set goes straight out through the house roof, and the other finds its way to the garage roof, so it must be 12 + 4.

 

[Earthstore]

Oh dear, this does not look good, apart from what you have mentioned, If an inverter is mounted on a board, it has to be fire retardant, not just plywood..

It should also be correctly labeled, sorry, but a marker pen does not conform.
Post some more pics of the rest of the install, panel mounting also would be good.

We are seeing far too much of this type of work....

 

[cbw]

I was wondering if they could write on the inverter about dual supply etc.....