[Kevin Sharpe]

A new thread documenting our home solar PV system.

Today (3rd March 2014) is a great solar day and at 12:15 we were generating just over 4,100W (3,013W SE roof, 1,088W NW roof) and charging the Tesla at 16A

 

[Kevin Sharpe]

another great solar day with 21 kWh produced in 11 hours... not bad for the 9th March

 

[Kevin Sharpe]

~4200W (3,001W SE roof, 1,182W NW roof) at 11am today charging the car at 16A

 

[hopbackguy]

Yep, the last couple of hours have been great here near Portsmouth as well , for the first time around 1245 I saw my output peak to about 3.2kW (about 50/50 E/W roofs). Big grin here!

 

[GBEV]

Yes, yes, yes the way to be master of charging is to experience that there will be no charge master .
According to PV Output.Org our E/W roof is at 19+kw and still doing 1.4 kw as I write at 6pm.
Will be smugging along on gallons of sunlight whilst the veg plot springs to life avoiding the need to use any supermarket free to use for £20 charge points!?
Also enjoy driving like the wind in spaceship leaf.
Thanks E'T oh that reminds me must "Call Home" !

 

[knoxie]

Yes same here on my e/w split 4kW system saw 3.3kW today and had over 20kWh out of it during the day, very pleased with that as there was a lot of cloud about and the load curve looked like a hairbrush in profile, the best money I have ever spent on anything apart from the house itself and the Leaf of course!

 

[GBEV]

20.4 kWh today. 3.2 Kw peak =16 Amp leaf charge. Fill in the gaps (no clouds) and it could have been full re-leaf plus some.

 

[Kevin Sharpe]

35kWh on Wednesday, peaking at ~4.3kW (~18A)

 

[Nigel Hunt]

Couldn't be left out of the gloating. This was Wednesday on my ESE 3.96kW system, installed in 2008. As an early adopter, I don't qualify for the high FIT payments like the rest of you. But I did it because I believe in it, not for the payback!

 

[Paul_Moxhay]

You have a shading issue. Your installer should have spotted that and advised you accordingly.

The thing about a solar array is that you only need a very small corner of just one of the array to be in shade and the output of the whole array drops to near the value of the shaded part.

What is causing the shadow? Can it be moved or cut down so that panel is no longer in shade at the end of the day?

This is a very basic error on the part of the installer and if you were not advised of this effect then I'd be going back to the installer and seeing if they could refund you for the panel that is in the shade and remove it... or at least consider if that would help.

It is very possible that removing the panel that is in the shade might maintain your array output for much longer so that although you have less panels you might generate more kWh.

This should really have been done when the array was designed because removing a panel might put the array voltage outside the recommended for the inverter.

Basically it requires a bit of looking at.

We looked at micro-inverters. At that time there were no MCS approved micros and the ones that did exist were nowhere near as efficient and modelling showed we got more output over the entire year by sticking with the normal inverter. Also, micro-inverters will not work with many panels... IIRC they need higher voltage panels to work... our 29V panels would not work with micros and so we would have needed to install the array using much more expensive high-voltage panels. It just wasn't worth it for a few extra kWhs.

Remember, if they are not MCS approved and installed by an MCS installer then you won't be eligible for the FIT.

We have a small amount of shading at the start and end of the day but our installer modelled the shading and we knew about it before installation and the array and inverter size were planned accordingly.

 

[Gary Taylor]

Hi Paul,
That really is one big drop out, is that really caused by a shadow on one panel, you must be quite frustrated to be getting only 8kw so far with a 2.4 system.

I have 3.68 and has generated 22kw so far today but is dropping off fast, but as a unscientific ratio comparison you should be enjoying @14kw so appear to be losing out big style.

Hope micro inverters can sort it for you

Gary

 

[Paul_Moxhay]

This was my pvoutput generation for Wednesday... we were away so there is only a background house use but you can clearly see out generation pattern for a 100% sunny day. Note that we are clipped at the start and end a little but too seriously... as you can see... we generated nearly 15kWh that day from a 2.4kWp array

solar 2 by Paul Churchley, on Flickr

 

[GBEV]

Here's the infuriating crash I get around 4:45pm at the moment. Almost all of the panels are in full sunlight, but one corner of one panel is partially shaded. The result, a huge drop in output.I'm really hoping switching to micro-inverters will fix this.


View attachment 667

Does your SMA inverter have Global Optitrac? If so it should be switched on. You can log in via bluetooth if you download Sunny Explorer then hit 0000 to enter as user or 1111 to enter as installer and select Global Optitrack yes/on form the settings menu. Instant shading problem solution built in to most new SMA inverters.

 

[Paul_Moxhay]

I feel for you Paul

It is more than just one panel isn't it.

I know this isn't much help to you now Paul but for others reading this thread... solar installers can model your property using solar modelling software and it can then create a movie showing any shading issues. I made one myself of my system but as I was using a trial version of the software I could put in all of my shading sources. An installer should have a full version of this software or something similar and if there is any risk of shading onto the array then you could ask them to model it and get a prediction. It looks at the sun position on every day of the year and creates an estimate of generation.

 

[Mizuno-San]

Anyone on here an MCS installer? My installer disappeared a couple of years ago. I had a 3kw system installed on the high FIT rate and bought a spare panel at the time. Since then, I've removed a tree that caused some shading so now have room to add the other panel (still within the inverters limits).
I've had differing views from local installers varying from 'just add it in, no one will care about an extra 10% or so' to some saying that I wouldn't be able to keep my current FIT if I add a new panel and others saying that I could add a panel but might need a new FIT meter.
Seems to me, the common sense solution would be to add the extra panel and claim the new FIT rate pro-rata?

 

[Paul_Moxhay]

Seems to me, the common sense solution would be to add the extra panel and claim the new FIT rate pro-rata?

Does make sense but I am pretty sure you can't do that. The FIT applies to the entire system.

 

[Kevin Sharpe]

Anyone on here an MCS installer?

@Thephoenixworks can help I'm sure

 

[Mizuno-San]

Thanks Paul, I've messaged him, although he doesn't seem to get on here much.

 

[Paul_Moxhay]

This really is lunacy; seeing as I am applying for a feed in tariff for generating ELECTRICITY, and my house is heated by a combination of a wood burner and gas, why does it matter how well insulated my home is (for the record it's double glazed, has energy saving bulbs everywhere and has about a foot of loft insulation down), but other homes in the street have EPC ratings of between F and D.

It does make sense if you consider the objectives. They are aiming to reduce overall energy use and reduce CO2 and emissions and solar PV is just a part of that. So, they want to encourage people to take all the cheaper and passive efforts first before they pay us for solar PV.

So they assume that most houses could be upgraded in other ways to achieve a D EPC rating with insulation, double-glazing etc so they want people to spend on those first before they pay for solar.

I guess houses with solid walls are a bit of an exception though.

 

[Paul]

I'm only discovering how much of a farce EPC ratings can be though, like so many tick-box rating systems. Well intentioned but not great in practice, especially if you have anything non-standard going on. Although it seems the assessors don't actually assess a fair few things anyway!