Decking Pergola with PV

[JohnMo]

Planning a new pergola on an existing decking.

It will also have two 500W solar panels in the roof section, these are to provide some rain relief above the table, and additional free (?) power. The rest of the roof will be slats at 45 degrees. These will provide a exit for wind and prevent lift and stop direct sunlight.

 

The structure will be all wood, with metal brackets as needed (£130 so far). Main posts 4" x 4", roof perimeter 6" x 2" (£120 so far). Still lots of wood left from house and summer house build, so hopefully they will contribute.

 

Max height above decking 2.4m.

Size 4.5m x 3.9m. Priced up a similar sized kit and were about £8 to 10k. Including solar, battery and all materials to make pergola looking at nearer £16 to 1700.

 

Panels 2x DMEGC 500W bifacial, mainly because they look nicer with a glass back than a normal panel with a white plastic back cover. They are £67 each. These will be connected to an Ecoflow stream Ultra battery/inverter. This comes with 4x MPPT charge controllers and a 2kWh battery. 2 MPPTs will used one for each panel, not the cheapest at £999, but includes the inverter.  The other two MPPTs will used later for another project maybe. The panels will lay flat and should generate about 560kWh per year. Not a lot but ok.

 

So far have ordered the wood to build the basics structure, all brackets for structure, PV and battery. 

[SteamyTea]

Apart from the looks, is there any performance advantage in having bifacial?

[-rick-]

Depends how much light hits the other side of the panels. If located on a dark roof, not much light will make it through (I think some does through the gaps between cells). On a angle or as a shade over a structure with light covered ground as a reflector I believe it can increase output 10-20%

[SteamyTea]

1 hour ago, -rick- said:

Depends how much light hits the other side of the panels

It is in Scotland.

They still celebrate a sunny day.

Nearly time for 17h 55m and the all important 47s for the sun show itself, and peaking at 56° above the horizon.

(I get 63° but only 16h 23m and 26s of daylight)

[Nickfromwales]

You can get Solarwatt panels which are frameless and less densely populated with PV, which allow more light through, if that’s of any interest / benefit?

 

They do another which is framed too, but a bit denser, still lets some light through though. 

 

You can see it here, on a gazebo / carport doodah I made for my mates solar company. This is the best pic I can find which shows it. 
 

 

The light lines under the panels are areas of clear glass with natural light coming through. 

[Nickfromwales]

The wooden table alongside it has the frameless panel as the tabletop. If you want a better pic of that I can get one? 

[JohnMo]

1 hour ago, Nickfromwales said:

Solarwatt panel frameless

Gee, they are expensive - £260 at 175Wp each. That's £1500 for the same power output as my sub £140 spend.

 

1 hour ago, SteamyTea said:

It is in Scotland.

They still celebrate a sunny day.

Nearly time for 17h 55m and the all important 47s for the sun show itself, and peaking at 56° above the horizon.

(I get 63° but only 16h 23m and 26s of daylight)

Around 700 miles further north makes a difference.

[Nickfromwales]

13 hours ago, JohnMo said:

Gee, they are expensive - £260 at 175Wp each. That's £1500 for the same power output as my sub £140 spend.

 

Around 700 miles further north makes a difference.

Yup. Anything “bespoke” seems to attract crazy uplift with costs, aka supply / demand, but just showing options so you can maybe source similar to suit etc.

[JohnMo]

Made a start, no photos yet.

 

First issue - solar panel has reduced in size, from dimension on datasheet. Total length stated is 2094, actual 1950mm. Throw away statement "due to technological progress dimensions may change"

 

So a couple of design tweaks needed.

[JohnMo]

So day 1 working on my own, will finish corner bracing tomorrow and look at PV mounting. Posts are 100mm square. Side rails are 6x2. Rear vertical posts are screwed to existing decking posts which go up to the height of the rear wall. Used 3x 200mm structural screws on each post.

 

[JohnMo]

Progress today - photo a bit squint, not the decking.

 

All diagonal braces fitted. Two stringers to hold PV panels, reduced in height by 30mm to match PV panels. Flashing tape installed on top of PV mount stringers.

 

That was all the wood ordered.

 

So additional 6x2 ordered to split the front and rear bays in to half for roof slats and for additional support for PV stringers - square edge 95 x 12mm wood ordered to make slats for roof.

 

Lots of 45 Deg spacers to make tomorrow for roof slats. Lots of wood to use from other projects for that.

[JohnMo]

Not much to show for the last couple of days. Plenty of work but photos don't show much.

 

Cut lots of spacers for the roof slats, these are made out of floor boards I didn't use in the summer house.

Installed the support ledge for roof slats and the first starter spacer for roof slats, to allow painting.

 

 

And finally sanded the whole structure prior to painting. Too hot to paint at the moment - for me and the paint.

 

Needed to a new sander, my black & decker sander gave up after 20 year - now realise how rubbish it was. Have now got a Makita BO6030/2 150mm Electric Random Orbit Sander, it's good, not cheap but good.

 

[marshian]

cracking on at a pace - excellent - looks good

[JohnMo]

Rain forecast tomorrow, so not sure of the progress tomorrow, but would like to reassemble the half wall, I took down, but make it slightly shorter, to miss the new front right pergola post.

[JohnMo]

A bit of progress before the rain. Previous wooden wall shortened and reassembled.

 

Hopefully the rest of the wood will arrive tomorrow.

 

Have an issue with Ecoflow, are now saying the item ordered is in short supply and delish delayed. Asked by how long and no reply by Friday, so will be in phone first thing tomorrow, to get a straight answer.

[JohnMo]

Started the roof and added some more structural timber to roof.

 

Ended up with a very short section of roof at end of the PV panels. But a plant will be located directly below so will be watered every time it's raining.

 

Started painting but rain kept starting so have abandoned that for now.

 

[JohnMo]

On 12/06/2025 at 14:03, JohnMo said:

Ecoflow stream Ultra battery/inverter

Delivery issues have made me cancel the order. So now will just add a 1kW string inverter.

 

A Viridian 1kW inverter ordered from city plumbing. All in the 1kW system will be under £500.