Semi DIY PV Installation. Comments Please

[smegal]

Hi all,

I'm a bit late to the party, I was a member of the "other" forum for around 10 years, and despite following the threads, I never had the means to do any home renewables. I sortof work in the sector, so have worked on plenty but not got my own hands on anything.

I am looking to install ~1 kW of PV at the end of my garden. I currently have a sparky booked for Monday (11th) to install the AC side. I'll then have some help from a friend who is a system designer from a PV company on the DC side (he has site experience, so not the blind leading the blind).

My house is 8m to the gutter level, so scaffolding would be prohibitively expensive. And I am trying to keep costs as low as possible. My calcs suggest that I'll get ~ 1 MMh per year out of 3 No. JA Solar 380W modules and a 1 kW Solis inverter when shading losses are accounted for.


Here is an image of the end of the garden where I plan to install the PV. My current plan is for the bottom edge of the PV to be about level with the rear fence line.



Here are scale 3D models showing the PV (note I didn't measure the height of the garage ridge, so it is approximated)






I plan on using 3 No. 3.6m 100X100 wooden posts, 2 No. 3.3m HDG Unistrit for the panel rails, clamps. I am hoping to use the offcuts from the panel rails to form 3 No. angle rails to mount the panel rails. The angle rails will be attached to the 100x100 posts using a Unistrit hinge, the angle will be made using 3 No. unistrut cantilever arms and unistrut hinges.

The DC cabling will run to my garage where the inverter will be installed adjacent to the AC isolator. I am undecided whether the DC isolaror will be near the PV or in the garage.

Does anyone have any suggestions, comments watch its etc?

[Petertc]

When I did my install I put the DC isolator near the inverter.
I think that the solis also has a low starting voltage which is good.
I ended putting in a growatt some days during the winter It wont even start due to the higher starting voltage.

Good luck hope that it goes well

[smegal]

One other question that I do have. How much postcrete should I use and how deep should I bury the posts?

[Fintray]

Any reason for placing the uprights where they are rather than at the bottom of the panels?
I'd go for about 500mm depth for the uprights and if you can wrap the ends of them with Denso tape as it makes them last much much longer.
As said previously DC isolator next to the inverter.

[smegal]

Any reason for placing the uprights where they are rather than at the bottom of the panels?
I'd go for about 500mm depth for the uprights and if you can wrap the ends of them with Denso tape as it makes them last much much longer.
As said previously DC isolator next to the inverter.

I placed the uprights 500mm off the garage. My thinking is that I don't want to connect to the neighbours garage, and trying to minimise sterilising too much garden. I was also trying to minimise overhangs although the uprights won't be centred.

Denso tape is a good shout. I hadn't thought of that. I was considering charring the buried part but I'll just go for denso tape on the ends.

[Joeboy]

Hey Smeagal, welcome here too, glad you got here. Gotta ask if you can stretch your budget to cover a slightly larger inverter to further future proof it?

Looks like £261 V's £341 to step from 1Kw to 2kW inverter...

Regardless,well played Sir.

[Fintray]

Any reason for placing the uprights where they are rather than at the bottom of the panels?
I'd go for about 500mm depth for the uprights and if you can wrap the ends of them with Denso tape as it makes them last much much longer.
As said previously DC isolator next to the inverter.

I placed the uprights 500mm off the garage. My thinking is that I don't want to connect to the neighbours garage, and trying to minimise sterilising too much garden. I was also trying to minimise overhangs although the uprights won't be centred.

Denso tape is a good shout. I hadn't thought of that. I was considering charring the buried part but I'll just go for denso tape on the ends.

Ahh, hadn't noticed that it wasn't connected to the garage, in that case make sure of plenty of postcrete as those 3 panels could put a fair load on the uprights when it's windy.

[smegal]

I had 6 bags per post in mind. Does that feel right. It is tall with a big sail at the top.

[Fintray]

6 per post should be plenty, just remember to dovetail out the bottom of the holes to help prevent any lift.

[AGT]

At the bottom of the post screw a piece of unistrut/timber off cut, across the post to make an upside down T

Post Crete/concrete and it’s never ( hopefully)pulling out with the wind load