DIY Solar summer house install

[welsh1]

Hi all

I am thinking about solar, like a lot of people here it seems! My house roof has funny dormers so limited space and none south facing.

I have a summer house in the garden which is roughly 5.4m x 3.4m

i have a 6mm 3 core electricity cable from the shed to the MCB. I was thinking can I install panels on the summerhouse roof. Its EPDM and ideally wouldn't want to puncture the roof but I suppose needs must. would not want to weight the panels with concrete blocks as concerned about such excessive weight.

i have had a quick look at panels etc and thought i could fit 6 - 480w panels at a very low angle maybe 20 degrees. so this is about a 3khw system

I have an electrician friend (unaware of project yet) would could do the work but they are not MCS certified. is this an option? anyone done similar? the pay in tariff is useless so not that that concerned. would a MCS certified sign off for a price? the power i don't use would go back to the grid i suppose, i have read somewhere you have to be careful you don't get charged for this ?! not sure if that's an issue. have one of the latest smart meters. also looking at battery totally unsure about sizes but say 2.6 - 5kwh. can this live in the summerhouse, this is about 45m away from the MCB.

house only has 4 people not a massive user of electricity, maybe 8-16 kwh per day

thank in advance for any advice!

 

[samcat]

Done this, self install on verandah on back of house (SSW facing), panels in series, then wiring run to the garage (about 8m, did the voltage/current and derating calcs for the run). 2kw of panels (8). Sparky signed off my work and then a simple G98 application to your DNO.
Garage was already wired with its own consumer unit, which had a spare way.
Solar inverter has to have a dedicated circuit.
AC Isolator switch by inverter, another by consumer unit.
DC Isolator by inverter.
Suitable labelling.
Make sure the inverter you choose is G98 approved.

Keep it under 16a (3.68 kW of inverter output) for an easy life, more than that and its a G99 application which is a lot more complex.

Dont worry about FIT (feed in tariff), its not worth the trouble IMO.

We added a box that monitors and diverts excess solar to our hot water tank.. Great reason to keep the hot tank, as it reduces our gas usage and tops up the hot water with the spare electric.

 

[welsh1]

Hey Sam thanks for the reply, some really good info there. Like the G98 application and informing the DNO. Hoping I don't need to upgrade the electrical supply while im at it !
do you have any more info on yours, what you bought, fixings etc ? Still at early stages but have asked numerous companies about brackets etc to install and no reply, seems everyone is busy

thanks again

 

[samcat]

Installed mine quite a few years ago now.
2nd hand panels, they were unused spares from a solar farm.. Wanted £80 a panel, then a small discount for buying 8. 2nd hand is cheaper these days. Dont buy with cracked glass. yes they may still produce power but the weather sealing is compromised.
From memory they are Q-Cell 270w panels.

Growatt 2kW inverter, 2000s. Second hand ebay special, paid £50, been working perfectly for a few years.
(this one: https://midsummerwholesale.co.uk/buy/Growatt-inverters/growatt-2000s)
The Growatt wifi dongle, so I have all data dumped onto their portal. Again, ebay special.

Using Unistrut rails and a set of suitable depth (45mm, as panels are 45 mm thick) mid and end clamps.
The panels will have instructions (online usually) of where abouts they need clamping. Follow this.

Suitable DC cabling and MC4 connectors. Bought a proper MC4 crimp tool (again ebay) and then resold it once done.

Make sure maximum wattage of panels is suitable for inverter - taking into account temperature coefficient (they get more efficient in cold weather, so cold spring/autumn in full sun they can produce more than 'plate' wattage.

Make sure total voltage is suitable for inverter (again, temperature coefficient)

Read and understand the G98 regulations. Its a bit wordy but most of it is obvious/sensible safety stuff.
https://www.energynetworks.org/indu...ion-of-fully-type-tested-micro-generators.pdf

Shopping list:
Solar Panels
Inverter
DC isolator
2x AC isolators
Suitable size DC cable
Suitable size AC cable
Rails and mountings suitable for your roof type
End clamps
Mid clamps
MCB with C curve for your consumer unit
Spare circuit on consumer unit

I think thats it...
For me, how to mount it onto rails caused the most head scratching, everything else was fairly easy to figure out reading the manuals/regulations.

 

[samcat]

For context, here it is installed.

Verandah is a bit ropey in places now, made from wrong type of timber. Being replaced this year/next.

 

[robj20]

I definitely want to do this I have room on a garage roof and kitchen roof, both flat.

Zero issues doing all the wiring myself just need to find a place to buy it all.
Even if it just deals with the 250w or so of idle power in the house that would be great.
I've heard that micro inverters are a good approach ie an inverter for each panel.
https://midsummerwholesale.co.uk/buy/enphase/iq7

 

[1pudding1]

For context, here it is installed.

Verandah is a bit ropey in places now, made from wrong type of timber. Being replaced this year/next.

What wrong with the wood? Not treated for outdoors? Also where did you get the unistrut from, im looking doing this soon on a car port? Ta.

 

[welsh1]

looks prefect to be fair, great use of space. told you do need planning if erecting on a flat roof however. with a Veranda you don't have that problem !

 

[samcat]

What wrong with the wood? Not treated for outdoors? Also where did you get the unistrut from, im looking doing this soon on a car port? Ta.

Not treated for outdoors. Its standard size to using some acroprops and replacing bit by bit works...

Bought from these guys, the shallow stuff and used L brackets from them as well. Works really well, would buy again.
https://www.unistrut.co.uk/product-details/p3300t

Get galvanized and earth bonded it (and the panel frames).

 

[samcat]

looks prefect to be fair, great use of space. told you do need planning if erecting on a flat roof however. with a Veranda you don't have that problem !

Its superb to be honest, that side of the house is s-sw facing so gets cooked, as luck would have it that the panels provide shade JUST outside the patio door in summer, but in winder they let the light (and heat) shine through. 10/10 would recommend getting this lucky (or planning where the shade falls at different times of year if you can)

 

[1pudding1]

Not treated for outdoors. Its standard size to using some acroprops and replacing bit by bit works...

Bought from these guys, the shallow stuff and used L brackets from them as well. Works really well, would buy again.
https://www.unistrut.co.uk/product-details/p3300t

Get galvanized and earth bonded it (and the panel frames).

Sorry to be dumb, but which clamps go with that rail? I cant for the life of me find them? Or are they 3rd party clamps for the actual solar panels? I found some unistrut info/brochure for solar panel clamps, but it was an Aussie site and they dont seem to be available over here (maybe my google skills are failing!? )

 

[samcat]

Sorry to be dumb, but which clamps go with that rail? I cant for the life of me find them? Or are they 3rd party clamps for the actual solar panels? I found some unistrut info/brochure for solar panel clamps, but it was an Aussie site and they dont seem to be available over here (maybe my google skills are failing!? )

ahh, should have explained.

I use the clamp bit and bolt from whatever rail system I could get cheap (second hand job lot), and channel nuts from unisturt. It sound a bit mcguiver, but works really really well.

https://midsummerwholesale.co.uk/buy/renusol-pitched-roof-mounting/end-clamp-silver
https://www.unistrut.co.uk/product-details/pnp06-pnp12a