2 strings or one

[sportyspice]

Hi all hope you can advise me
I have an on going problem with my inverter
My installer wants to change the inverter to a German that i don't know the name of yet
He is telling me that his inverter will only work on a high voltage and i have to put my 2 strings of 8 235w panels into one string
Is this a good idea or not, will it affect the systems output
Cheers
Paul

 

[SolarCity]

That is a difficult question to answer without knowing some more details.

What is the ongoing problem you have been having with your inverter? Does your system have any shading issues at all? Are all panels at the same orientation and pitch?

 

[sportyspice]

The problem is that it keeps going out on fault saying that the AC side is going outof the limits
But im Sure this is not happening as i have been moneriting the supply for a number of days with a voltage meter and the range has been between 235/245v.
My system is 16 panels in to strings sw facing no shading at all portrait
I have posted a few days ago about the inverter powfuter from china
Cheers Paul

 

[Earthstore]

It may be that the AC supply cable going to the inverter is too small, causing a voltage loss, so the inverter has to raise its voltage to match the grid voltage ( this has become a very common fault as some installers do not calculate voltage drops on AC cable)
(it should be less than 1%)
Or it may be that the inverter is not set up for the UK voltage, also another common problem.
I hope this helps.

 

[sportyspice]

Thanks Earthstone the inverter is set up to G83 so should be ok
The supply cable is 4mm t&e 5mtr run
I think the installer is having the same problems on other installs.
What are your thoughts on changing from 2 strings to just the one ???

 

[Earthstore]

It all depends on the inverter, if the voltage of your panels is lets say 37v, so 37x16= 592v, so the inverter has to be able to cope with that voltage, or if split into 2 strings 37x8=296v so if you have an inverter with a voltage range starting at 300v, then it would not start up.
If you have any shading, then you may be better to install an inverter with 2mppt's, and have 2 strings to maximize performance.
If you match an inverter correctly to a system, you can increase your daily output quite considerably therefore you will return more £££'s.
To get it right, things need to be calculated, work out different options to see which is the best.
Sadly, there are some installers that just plug one in and see if it works.
I hope this helps.

 

[mmccx]

The problem is that it keeps going out on fault saying that the AC side is going outof the limits
But im Sure this is not happening as i have been moneriting the supply for a number of days with a voltage meter and the range has been between 235/245v.
My system is 16 panels in to strings sw facing no shading at all portrait
I have posted a few days ago about the inverter powfuter from china
Cheers Paul

Measure the frequency and voltage of you incoming supply! you may have a high voltage or frequency