How worried should I be?

[DanB]

I'll probably start a different thread, as I see the two issues (safety and installation, and performance) as separate. However, I will say for now that my generation meter reads 25kwh today, and the installation date was 14th December.

PVOutput had a problem with my postcode, as apparently ours changed in the last few years. However, I think I've got it sorted now, and we're at Solar Bates 4.000kW | Live Output

(I think I'm a couple of hundred yards away from FB!)

 

[FB.]

(I think I'm a couple of hundred yards away from FB!)

I'm in CB24 but we used to be CB4 until a few years ago (PVOutput hasn't worked out the Cambridge postcode changes).
I'm just a short distance up the A10 from Cambridge.
Which area of Cambridge are you in?

 

[DanB]

We're in Milton.

 

[FB.]

We're in Milton.

So am I.

But I haven't noticed any 16-panel arrays facing SouthEast(ish) go up in the last couple of months.

Shall we have a race to see who finds the other person first?

"Knock knock.....Hi Dan.....oh, you're not Dan? I'm so sorry!".

 

[DanB]

I figured as much from the PVoutput map. You'd be hard pushed to notice ours, because it's tucked around the back of the house, and also split between garage and house, so it's unlikely you'd ever see all 16 at the same time. I have a couple of candidates for yours though

There's a bunch of houses along the northern side of the school field that I just WISH would get arrays - they must have the perfect orientation and no shading because of the playing field. I look at them with envy!

 

[steg22]

They could be using a subcontractor for the connecting, if so they need to find a new one quick!

 

[FB.]

You'd be hard pushed to notice ours, because it's tucked around the back of the house, and also split between garage and house, so it's unlikely you'd ever
see all 16 at the same time.

I know where you are..............:38:

I'll give you a clue for mine: it's one of the evil twins (count the panels on the evil twins and you'll see which one is mine).

I could see all of your panels by going into the next Close along.

Looks like black-framed 10 facing East on main roof and 6 facing South on single-storey garage roof.
I hope they've wired them as 10+6 and not 8+8! The 10x East-facing will probably only rarely hit 100% of potential, so although PowerOne would not be happy if they knew you had 2.5kW running into a 2.0-capped input, it's unlikely that your 2.5kW of East-facing panels will ever get much above 2.0kW.

The inverter will tell you the string voltages under the heading of "VP1 and VP2" and this can be used to calculate how many panels are connected in each string - usually about 30Volts per panel at optimum, but does vary with weather conditions and also the design of the panel (Sanyo are higher voltage).

 

[FB.]

Power One inverter string configuration tool:

Power-One Aurora Stringsizer?

.

 

[DanB]

I'll have a look at the string voltages the next time the sun is up.

Well, it's been a week since I emailed the company expressing my concerns and sending them the photograph, and I've heard precisely NOTHING. Time to get concerned and amp up the response a bit perhaps?

 

[Orffyreus]

Hi Dan, regarding performance and as FB has suggested, I would check the string voltages. Every 30 mins will give you a good idea where the problem may be. Looking at your readings on PVOutput your generation appears to rise very quickly about solar noon. As you have 10 panels facing East ie: best before noon and 6 facing South, after noon, I would suggest that the problem lies somewhere with the 10 panel configuration, although what the problem is, I cannot say.

It could be shading or again as FB suggested it could be how the strings are configured, put simply and in my opinion, the 10 panel array is not performing as it should.

Your installer should have left you with a wiring diagram but considering what we have heard so far I doubt he did.

As well as getting the problem rectified, Trading standards and name and shame, are the way forward.

 

[DanB]

I really don't think there are any shading issues - there certainly aren't any tall tress around, and once the sun has risen above the horizon, our roof is in full view.

 

[Orffyreus]

Similar effects to "Shading" can be caused by incorrect string set up in split arrays. BTW which model inverter do you have? The Aurora inverters require manual setup when strings are installed with differing panel configuration. If you look at your output graphs you will see that AM "East" is very low compared to PM South considering panel setup. Obviously I am not aware of weather conditions in your area.

 

[DanB]

Orffyreus, that's really interesting. The Aurora Communicator software connected via the RS485 interface, reads the model as PVI-3.6-OUTD-UK.

 

[Ian-LS]

has the inverter been put in dual MPPT mode and not single MPPT mode? AFAIK power one 3.0 OUT and 3.6 OUT come as standard already set to dual MPPT

 

[Orffyreus]

Here is a link to a video that shows how to check and adjust your inverter.... not that I am suggesting you should prod about :93:

If your system is split 10/6 each channel should have been set up "independently" it would be possible for an 8/8 configuration to be set in parallel but not advisable for your installation because of significant difference in orientation of panels.

Power-One Chomeless Single Video

Just to confirm, you have 10 panels facing East and 6 facing South.

I have been monitoring your system on PVOutput for a few days and performance pre 9AM is extremely low (low insolation perhaps) but rise at the time when the south facing panels would be exposed to the sun, my reason for suspecting the problem lies with the 10 panel array.

If this were my system I would be tempted to identify each string and disconnect each in turn over a couple of days to see how each string was performing independently.

PS, Perhaps best to disconnect and make safe any DC connectors at night.