Hi all
I don’t have roof space, but need to add more panels.
I have a double story, have a 8.4m wall, against which I can make frames fit to hold the panels.
was thinking due to distance to neighbour to put them length wise against the wall.
thinking, smaller, more panels vs larger less.
Suggestions on panel make model options.
Will be buying a dedicated MPPT for this string.
Currently have 3 x AmeriSolar 330w panels, facing North, this will also go north, but on own MPPT.
G
Smaller panels mean more mounting and on brackets on a wall, it ain’t easy. I’ve done the same.
Price difference between smaller panels and bigger isn’t much. Think inverter warehouse still have 555w jinko panels for R2300. Cost per watt, I don’t think you can find anything cheaper.
My mission is to get as many Watt’s as I can in one line against that wall…
G
I’ve only got a west facing roof on a small section of my house. Rest is flat roof that I have a lots of rose pots on.
I’ve got 8x 420w panels on wall brackets facing East and another 9x 460w panels (4 on 1 section and another 5 on another ) facing north.
On the west roof, I’ve got 8x 360w panels on 1 string and another 8x 390w panels on another string. Recently, I was considering getting rid of the 360w panels and replacing them with the 420w and then getting bigger panels to replace the 420w… like the ones I quoted above. It’s too much effort though so decided against it.
If I did though, I would use the biggest panels that my inverter could support. I’ve got sunsynk so the Imp of the panel is the limiting factor for me.
… i got a Victron… so will be buying a separated/dedicated MPPT for this string, and with 3 or 4 panels I’m not gong to max any mppt out anyhow.
at 3 x 550 I’m just over 6.5-6.8 m by my reckoning, leaving space…
want to see if i can get 4 panels in that fill larger stretch of the 8.4 meters.
G
If I may make a suggestion to consider.
It is likely on your wall shade may approach or recede from a certain predictable direction.
Take for instance if it is a west-facing wall with an overhanging eave.
It will be completely in the shade at noon, and the sunlight will start to reach the panels as the afternoon wears on from the lowest to eventually the highest panel.
Now consider how a PV panel is physically constructed and how shade affects it.
If a panel is in portrait, shade on the top row of PV cells will shut the panel down.
However, if the the panel is in landscape shade on the top row of cells will only shut down 1/3 of the power.
In other words, how you orientate your array portrait or landscape can have a big effect on production and the length of your solar day.
Can you send a photo of the wall and the space you have to the boundary or garden. I would go with a landscape orientation and gain more space for more panels. You would also gain a 2.2m shady “roof” which could be nice.
If you go bifacial then that could also help production.
The % gain of a bifacial imo has not yet justified the higher cost…
I need to go landscape for 2 reasons.
Distance to boundary, see picture and then wind, for a landscape I have a frame made that will be able to keep panel safe, we have high winds. Portrait no chance.
No need for nice shade or anything on this wall.
The wall shows perfectly north. PlN is to fit panels right up against the top gutter.
G
Jaco. Would bifacial be that day for a string of 6 some are Portia’s and some landscape?
G
Bi-facial, from what I read when they came out, works ideally on ground-mounted structures.
Saw a vid of a guy testing them in snow on a ground-mounted array, some normal, some bifacial. They worked better seeing that they got rid of the snow faster/less snow. We don’t have snow.
He had snow, one has to put some white reflective material like white stones/white concrete, or white whatever underneath the panels to optimally reflect the light back at them from below.
Made sense that.
How it can work mounted closely to a roof sheet, that is not even painted white, makes me wonder about the gains … if any.
My problem I’m 1m from boundary wall.
I can’t fit my panels portrait, otherwise they will overhang into neighboring yard.
G
Get a really good product to cover that steel with, or it will rust. Ask me how I know 
After that I swore I’d never use steel again. For my next frame I bought angle aluminium, and bolted the frame together. Not only did it not rust, it is so much faster to chop things with a mitre saw (obviously with the right blade), and no need to paint and wait for it to dry.
… to make it worse, I’m 200m as the crow flies from the beech…
G
The brackets will all be galvanized. The mounting bolts will go right through the wall as I don’t think rawlbolts will hold in cinder block. The panels may also be more difficult to steal as Neighbours will hear or see any activity and to get at them one needs to work on an awkward job from a ladder. Alarm beam going up too and a camera.
Please make sure you neighbor is happy… I think you may have a bylaw issue with a permanent structure encroaching on the 1m limit…
Luckily i have a friendly neighbour… and neither of us has plans to move.
but also don’t want to go over the boundary, thus the portrait thinking.
G
Landscape will work just fine on the PV panels. Just note if you do put them on you most likely will need to add a gutter. Even if you have a friendly buddy next door, your roof is not allowed to throw water over your boundary wall.
Also if you are close to the ocean then don’t mix aluminium brackets and stainless bolts. They make an electrolite from the salty mosture.
Also hoping to see some extra generation due to the reflected light from the wall above.
