Replace 2.5kw system help

[dave1967]

It is a genuine solar installer that did the work. I think its just an oversight re the inverters not powering up. So the panels will have to be rewired to go to one inverter then?

[sgt_woulds]

That's not oversight, it's incompetence.  It's about a lack of fundamental knowledge of how a PV system works.

 

Any solar installer would check the system requirements before wiring the system.  To complete the work they need to update the schematics of the system, (displayed at both inverter and mains incomer locations) to show how the panels and inverter are wired.

 

If you've paid them on the basis of their alleged knowledge then they should be liable for the cost of scaffolding and rewiring to remove the redundant lengths of DC cable, (which will affect the performance of the system by a negligible amount, but the principle remains).

 

They should also ensure that the inverter wiring and labelling are compliant with the wiring regs and MCS requirements and the grid regulations, (at least the ones in place when the system was first installed - G83 I think -G98 came in around 2020 from memory). 

 

I'm unsure if there are any additional requirements under the 18th edition WR - I've been out of the game for quite a while - but I'm sure there are some up to date electricians on here who can advise further...

 

 

 

[Dillsue]

3 hours ago, dave1967 said:

It is a genuine solar installer that did the work. I think its just an oversight re the inverters not powering up. So the panels will have to be rewired to go to one inverter then?

Get the correct inverter to match the panels. With 3 panels on an inverter you'l likely be on the limit of reaching the 120v start voltage, as you've discovered. 

Put 4 or more panels on one inverter and youll hit the start voltage but be exceeding the max power input of your 1200s so be wasting valuable FIT generation. If you've already got 2.5kw of panels and adding another 2.5kw you'll be well over the combined max input of the 2xSB1200s. You are adding to the system rather than like for like replacement??

 

You do have the option of reworking your FIT system by changing the inverter and adding the new panels to the larger inverter. As you're making significant changes might be worth discussing with your FIT payer in advance as some don't have a clue....Scottish Power are utterly useless. Hope their CEO is reading this:)

Edited November 26 by Dillsue

[Dillsue]

1 hour ago, sgt_woulds said:

That's not oversight, it's incompetence.  It's about a lack of fundamental knowledge of how a PV system works.

 

Any solar installer would check the system requirements before wiring the system.  To complete the work they need to update the schematics of the system, (displayed at both inverter and mains incomer locations) to show how the panels and inverter are wired.

 

If you've paid them on the basis of their alleged knowledge then they should be liable for the cost of scaffolding and rewiring to remove the redundant lengths of DC cable, (which will affect the performance of the system by a negligible amount, but the principle remains).

 

They should also ensure that the inverter wiring and labelling are compliant with the wiring regs and MCS requirements and the grid regulations, (at least the ones in place when the system was first installed - G83 I think -G98 came in around 2020 from memory). 

 

I'm unsure if there are any additional requirements under the 18th edition WR - I've been out of the game for quite a while - but I'm sure there are some up to date electricians on here who can advise further...

 

 

 

No requirement to meet any MCS standards....all optional if your not using an MCS installer.

 

Single line schematic is only required at the incoming supply and only needs to show the 240vac wiring so the DNO knows where to isolate. No need to show panel wiring unless you want to. 

 

From the installers point of view he seems to have been asked to install kit supplied by the OP. Not sure I'd be slating the installer when he may well have assumed someone else has matched the panels to the inverter. Installer should have raised the issue of lack of G98 compliance though!!

Edited November 26 by Dillsue

[dave1967]

It is a genuine solar installer that did the work. I think its just an oversight re the inverters not powering up. So the panels will have to be rewired to go to one inverter then?

[dave1967]

What happened was i was quoted to replace panels which the solar company  selected.

Offer then accepted by myself.

Third party company then turned up to do the install. They told me the issues and fixes when they left.

Original company now saying I need to add more panels but that isn't efficient and will breach and negatively affect my payments during average weather but i cant benefit in full sun as limited. Other option is single inverter and rewire or leave as is with 2 strings. I am going for them to install 2.5kw inverter, not sure about wiring.

 

[Dillsue]

1 hour ago, dave1967 said:

It is a genuine solar installer that did the work. I think its just an oversight re the inverters not powering up. So the panels will have to be rewired to go to one inverter then?

Not to your existing inverter as you'll be overpowering it...3 panels won't give you enough start up voltage, 4 or more will exceed the 1300 watt power input limit 

[Dillsue]

1 hour ago, dave1967 said:

Original company now saying I need to add more panels but that isn't efficient and will breach and negatively affect my payments during average weather but i cant benefit in full sun as limited. Other option is single inverter and rewire or leave as is with 2 strings. I am going for them to install 2.5kw inverter, not sure about wiring.

 

If you're having a new single inverter then you can theoretically wire your 6 new panels in a single string into the inverter. Is there any shading in the new panel location?

 

You won't breach your FIT payments for adding more panels. You get paid only for the generation attributable to the original capacity. If your original FIT system was 2.5kw(10x250watt??) and you add 2.5kw(6x410watt) then you only get paid for 50% of what your generation meter records. Just let your FIT payer know about the additional panels and they'll sort out the pro-rata payments. 

[dave1967]

1 hour ago, Dillsue said:

If you're having a new single inverter then you can theoretically wire your 6 new panels in a single string into the inverter. Is there any shading in the new panel location?

 

You won't breach your FIT payments for adding more panels. You get paid only for the generation attributable to the original capacity. If your original FIT system was 2.5kw(10x250watt??) and you add 2.5kw(6x410watt) then you only get paid for 50% of what your generation meter records. Just let your FIT payer know about the additional panels and they'll sort out the pro-rata payments. 

On 25/11/2024 at 19:50, SteamyTea said:

Which SMAs you got?

Why have you got 2 of them?

 

[dave1967]

Ok thanks for that. Will have a think about the next step.