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

[Worcester]

OK guys, so 2 inverters are 2 SSEG's if you keeping to the STRICT interpretation, surely juniperz will need a G83/1-1 Stage 2 application, it might be one site, and the sum might be below 16A, however that is NOT the strict interpretation of G83/1-1 Stage 1

Surely a better implentation here would either be solaredge or enecsys.

Starting from scratch if you guys had a 12/4 to do what inverters/configurations would you have used?

 

[Noshocks]

I would have reccomended a 12 panel system, I am not convinced that the extra expense and hassle of the four panels are justified. Trouble is as we all know we may well lose the job as the next installer convinces the customer that 16 panels can be fitted, and then it ends in this situation.

 

[JulianC]

Would probably quote for the option of a 12 panels system using a 'traditional' inverter and a 16 panel system using Solar Edge

 

[juniperz]

If its aspare way on the rcd side you will have lots of inconvenience with tripping etc
if not just tell this company you will deduct the £150 as you don't require a new distribution board

Yes, I have already told them that.

Im concerned you should be using this company at all after all your concerns

I am concerned too - but given that I have paid a 20% deposit, my house is surrounded by their scaffolding, their rails are on the roof, all the wiring is in place and there is a inverter installed, I feel I have to give them the chance to propose a new configuration before I tell them they need to undo everything and give back my deposit. This may look worrying as an outsider - imagine being us!

 

[juniperz]

Would probably quote for the option of a 12 panels system using a 'traditional' inverter and a 16 panel system using Solar Edge

That's two votes for Solar Edge. Can someone explain why this is the best solution? I could suggest it to the installer. Let me guess - is it really expensive??

 

[JulianC]

That's two votes for Solar Edge. Can someone explain why this is the best solution? I could suggest it to the installer. Let me guess - is it really expensive??

Basically, the single or dual MPP tracker function is taken out of the inverter and individual MPP trackers (power optimisers) are fitted to each panel (usually mounted to the rail behind it). Therefore, the output of a particular panel is optimised, independently of what is going on with those around it. Such a system can accommodate different roof orientations and pitches and even different types of panel in the same string. The last job we did was the first time we fitted one but it was the only real option (3 panels SW facing on a main roof at 50 degrees and 7 panels W facing on a garage at 45 degrees, with added shading complications). Does cost more than a similarly sized Fronius or SMA inverter, but not massively so tbh. Dunno how much the cheap Chinese inverters cost....

 

[juniperz]

If this is the right inverter, it doesn't look much different in cost compared with the Growatt 3600 that they originally quoted.
Solar Edge Inverter 3680W 16A AC Clamped - SE-3680 at Swithenbanks Alternative Energy | Grid Tie Inverters | Solar Photovoltaic
Presumably it is the MPPTs for each panel that bump up the cost.

 

[JulianC]

One of these per panel: Solar Edge 250W Power Optimiser with MC4 Connectors at Swithenbanks Alternative Energy | Grid Tie Inverters | Solar Photovoltaic

 

[juniperz]

I couldn't resist downloading the Solar Edge Site Designer software

The software doesn't seem to include the UK-specific 3680W 16A AC Clamped - SE-3680 so I uesd the 4000

 

[juniperz]

With a conventional inverter, the wiring seems to be in series for each string, with the panels daisy-chained.
With a Solar Edge Inverter 3680W 16A AC Clamped - SE-3680 and 16 lots of Solar Edge 250W Power Optimiser + Panels, are they wired in parallel, so that 16 pairs of wires need to find their way from roof to inverter?