PV Expansion - Wall Mounted Experimentation

[Sim_C]

Thinking about a wall mount array myself to utilise a currently unused MPPT input, on a South facing side wall with just a small en-suite window at first floor level. It should comfortably fit 4 panels, all portrait, in 2 groups of 2, each side of the roughly central window.

With my electrical bias and limited mechanical knowledge, I was thinking of using unistrut or equivalent bolted to the wall in 6 vertical lengths of 1500 mm, and utilising the 4 fixing holes on each panel frame (1100 x 1095 mm spacing). It may look a bit industrial, but should be secure.

Any tips on the mounting system?

[Stinsy]

Mounting panels to Unistrut is simple just bolt and washer into a zeb.

[smegal]

Mounting panels to Unistrut is simple just bolt and washer into a zeb.

Yeah, most rail clips have m8 bolts, so you just get rid of the bottom and bolt on to a zeb.

[nowty]

Do it , only thing to add is something to stop them slipping down.

[Sim_C]

Many thanks for the input.

The issue with rail clips is the potential slippage down under gravity of vertically mounted panels, as commented.
And the panel fixing holes cannot be used directly to the unistrut as the panels will only be spaced 41 mm from the wall, so no room to get a spanner in to tighten.

Hence the idea of using flat L brackets, bolting them to each panel first, then the bolts for fixing the brackets to the unistrut are exposed for tightening.
I will update the image with labelling for clarity when I get a chance.

My other concern is galvanic corrosion of the aluminium panel frame when in proximity to the galvanised steel unistrut, hence the images of SS bolts and washers between components. Is this actually necessary, or overkill?

[nowty]

I would definitely use stainless steel bolts and washers as its outside, but with regards to galvanic corrosion, it did come up before in a thread and I think it needs to be in contact with an electrolyte, ie, it needs to be in a permanently wet condition, so I would not worry too much.

[Stinsy]

Many thanks for the input.

The issue with rail clips is the potential slippage down under gravity of vertically mounted panels, as commented.
And the panel fixing holes cannot be used directly to the unistrut as the panels will only be spaced 41 mm from the wall, so no room to get a spanner in to tighten.

Hence the idea of using flat L brackets, bolting them to each panel first, then the bolts for fixing the brackets to the unistrut are exposed for tightening.
I will update the image with labelling for clarity when I get a chance.

My other concern is galvanic corrosion of the aluminium panel frame when in proximity to the galvanised steel unistrut, hence the images of SS bolts and washers between components. Is this actually necessary, or overkill?

Should be no slippage. Bolt and washer works fine but you can screw m8 panel clips into m8 zebs if you want. The galvanic reaction between aluminium and galvanised steel is so weak as to be no problem unless you’re next to the sea, you can get panel mounting clips with plastic inserts between the aluminium clip and galvanised bolt for use if you’re by the sea. You should definitely avoid stainless steel and aluminium being in electrical contact though.

[chris_n]

Why not run the unistrut horizontal and use straight rather than L brackets, no chance of slipping then . You can overlap the brackets if you want to minimise the gaps.

[Joeboy]

I wouldn't give a worry to galvanic corrosion and I'd use s/s fasteners for ease of disassembly.

If genuinely worried buy and fit a small magnesium anode to the system where you can monitor it for activity?

I wouldn't bother though but it is an.option.

https://www.anodeoutlet.co.uk/magnesium-anodes/

[smegal]

Many thanks for the input.

The issue with rail clips is the potential slippage down under gravity of vertically mounted panels, as commented.
And the panel fixing holes cannot be used directly to the unistrut as the panels will only be spaced 41 mm from the wall, so no room to get a spanner in to tighten.

Hence the idea of using flat L brackets, bolting them to each panel first, then the bolts for fixing the brackets to the unistrut are exposed for tightening.
I will update the image with labelling for clarity when I get a chance.

My other concern is galvanic corrosion of the aluminium panel frame when in proximity to the galvanised steel unistrut, hence the images of SS bolts and washers between components. Is this actually necessary, or overkill?

Good quality zebedees have teeth that should dig in to the back of the unistrut profile reducing slippage, so rail clamps would be ok You could also put another clamped zebedee below the one holding the panel for belt and braces, although panels only weigh less than 30kg, so not heavy.