Roof PV install. Experiences?

Roof PV install. Experiences?

Author
Discussion

V40TC

1,994 posts

183 months

Saturday 7th May 2016
quotequote all
Ours is a 4Kw installation of 16 panels
with Spring arriving average is 25KW produced per day so far,
max seen so far this year was 30KW
biggest difference I noticed was production in cloudy conditions etc
after I cleaned the Panels there was a fair amount of bird poop and Dirt on them.
we have had the installation since Nov last year when we moved in
next quarter payment Due end of May so will get an idea of the returns.

Install was paid for by previous owners and was £7.5k.
panels on South facing roof elevation.

11-11-15 till 02-12-15 production was 91kw giving us £16.54

Edited by V40TC on Saturday 7th May 05:35

herewego

8,814 posts

212 months

Saturday 7th May 2016
quotequote all
Power units are kW
Energy units are kWh

caziques

2,567 posts

167 months

Saturday 7th May 2016
quotequote all
The major problem with electricity is storage, so the overall equation is capital cost versus the kWh produced - and what happens to the excess?

Prices in China are now US$0.50 per watt, so 7290 watts would cost US$3645 - my personal view is that micro inverters are far better than string (shading or one bad panel only leads to a small drop in output) - but micro inverters are US$120 each - which would add another US$3240.

Plus mounting brackets and install etc etc.

Any sort of battery has a significant extra cost, is relatively small in capacity, and will have a finite life.

gazapc

1,319 posts

159 months

Saturday 7th May 2016
quotequote all
Just out of interest, what paperwork took a year to sort out?

I'm sure you have, but I hope the price has been renegotiated since last year considering reduction in costs and the big cuts to feed in tariff payments since January. Do the finances actually stack up? Great if so.

7 kW is a big domestic system! Were the DNO fine with connecting that much?

Edited by gazapc on Saturday 7th May 09:56

SystemParanoia

14,343 posts

197 months

Saturday 7th May 2016
quotequote all
A pair of battery packs from sime crashed nissan leafs or teslas should do for storage and reuse overnight smile

Better than a crappy array of lead acid rubbish batteries

mikeiow

5,287 posts

129 months

Saturday 7th May 2016
quotequote all
I reckon we reduced our usage by about 1/3rd - problem being you generate in the day but need at night, and in winter you may not generate much at all!
Not sure if you get FIT payments - they were the thing that made the panels financially viable - without them I reckon we probably saved about £300 per year!

VEX

5,256 posts

245 months

Saturday 7th May 2016
quotequote all
Depending on how you heat your water, have a look at immersun boxes.

They measure the amount of electricity your producing and using and diverts any excess to another circuit. We have one of the early ones and in about 3 years we have diverted over 700kwh of energy into our hot water. The newer ones have two or three prioritised outputs for water and underfloor heating options etc.

V.

944fan

4,962 posts

184 months

Saturday 7th May 2016
quotequote all
Are you using micro inverters on that setup? That's a lot of panels and one chimney stack or tree causing a bit of shading is going to impact production across the whole lot

ETA - just re-read your OP. One transformer. Hope the panels are clear of overshadding

Dr Doofenshmirtz

15,186 posts

199 months

Saturday 7th May 2016
quotequote all
Yep...one panel going into shade will affect the whole system. This is why micro inverters are better if you can afford it.
Ate all the panels facing in exactly the same direction?

Paul Drawmer

4,865 posts

266 months

Sunday 8th May 2016
quotequote all
O/P is using JA Solar, I think that some of their panels have built in optimisers for eliminating partial shading problems.

Not sure what the OP is looking for here, the incentives in NL are not the same is UK, and there are plenty of internet sites that will give generation predictions based on Latitude, orientation and pitch of the panels.

Paul Drawmer

4,865 posts

266 months

Sunday 8th May 2016
quotequote all
Your single transformer (inverter) will be a large and expensive unit for 7kWp. It may be worth considering placing it in a location that does not subject it to high ambient temperatures.

Mine is in the roof space, which can get HOT, but I have tried to minimise heat build up by installing roof vents to supplement the eaves venting, so that there will be some airflow through the roof on days like today to take the heat away. I have also thought about mounting an external fan to cool the heat sink area of the inverter. Heat is one of the main killers of electronics, and an enclosed roof space can quickly rise to over the recommended ambient operating temp of the inverter.

Similarly, if you mount it in a cupboard it will get hot, as the inverter itself does produce some heat.


bobtail4x4

3,701 posts

108 months

Wednesday 25th May 2016
quotequote all
it should have a scaffold at that height.

herewego

8,814 posts

212 months

Thursday 26th May 2016
quotequote all
Is that safety rail attached to the guttering?

IIIRestorerIII

841 posts

227 months

Thursday 26th May 2016
quotequote all
That does look like a SolarEdge inverter and the quote mentions a SolarEdge optimiser included with each panel. Makes sense as with the different directions of the panels they will all be generating different power.

You should also get access to the Solaredge portal so you can see how much your system is generating down to each individual panel.

herewego

8,814 posts

212 months

Saturday 28th May 2016
quotequote all
The monthly figure is higher than the lifetime figure.