Worcesterlad Problems with a new solar pv installation

[Worcesterlad]

Hi my handle is Worcesterlad and this is my first post,
I have 16 panels of PV on a roof which is south facing, no shadow and 35 degree elevation, perfect position.
The first string is giving 115volts and the second is giving 175volts, the most output is 2.3kW.
When you isolate a string then reconnect the voltage goes to 280v (full sun at midday....no shadow) then as the invereter starts to convert DC to AC the voltage drops back to the figures quoted above.
Is the invereter faulty?
Has been installed 4 weeks and never generated more than 2.3kW.
Any advice or has anyone had a similar problem?
Thanks

 

[ExtremePV]

Can i give make/model of panels and inverter? Are the strings equal length?

Ken

 

[Ian-LS]

what inverter is it? and what are the string configurations?

 

[Worcesterlad]

The inverter is Samil SR - 4000TL
There are two strings of 8 panels

 

[davidcaulfield]

Equal length strings?

 

[Worcesterlad]

Yes Equal strings

 

[ExtremePV]

Doesn't sound like equal strings. What panels are they? (so we can work out what the voltages should be)
If they really are equal...then sounds like duff panel / connection to me?

 

[Worcesterlad]

there are 16 Suntellite 250w panels
Understand your comments and my thoughts are going in the same direction, but why does both strings each give 280v when switched on before the inverter kicks in to convert to AC.
It is like a back EMF building up to dampen the output.

 

[infinity]

The voltage will drop once it has connected to the grid as it finds the MPP range.the voltage you see before startup is Voc open circuit voltage

 

[Gavin A]

can you post up a picture of the installation?

something ain't right, get the installer back to check it out