Shedhenge

[Oldgreybeard]

Should be fine, I'd wrongly assumed it was a loft space, rather than a loft room. The loft at our old place used to get extremely hot in summer, hot enough to make even a brief trip up there very uncomfortable. Did make me wonder at how that might effect electronic stuff.

[spread-tee]

I'm starting to get some bits together for the upcoming project, specifically the 48V busbar stuff.

Would it be okay to make the busbars from flattened 15mm copper tube, 2 strips bolted together would have a CSA of about 55mm2 which would easily capable of carrying the max fused load of 100A over a distance of 20cm or so wouldn't it??

The other thing I am wondering about is the 48V DC cabling, I have quite a lot of 25mm2 meter tail offcuts but it is of course 7 strand or whatever, whereas I know this cable is usually multistrand, does that really matter for fixed cabling ?? I've never really understood the thinking here unless it is purely a mechanical consideration.

TTFN

Desp

[nowty]

25mm2 cable is ok for 100A, same spec as Pylontech cables. I got a slightly lower CCA for the 2 x 15mm tube's but I partly guessed based on a 0.7mm thick wall but my quick and dirty calc still came out over 30mm2.

I personally tend to buy copper strip off fleebay, but copper is copper, so why not.

Solid, 7 strand, multistrand, there are some differences but for a short battery connection, I wouldn't overthink it. If you have to make difficult bends then the more strands the easier your life is.

[spread-tee]

Thanks Nowty, I measured the wall thickness at .84mm but I know there are variations in pipe thicknesses, I may even triple it as I do like OTT when it comes to this kind of stuff.

It has actually been quite good being quarantined with Covid, last tuesday til thursday were pretty bad but since then I have been able to potter about the place with a tape and notebook working out a plan for all these shenanigans

I am seriously considering mounting six panels up on the lofty flat roof on a timber framework, they will be lifted up by 25cm at one edge so basically at less than ten degrees inclination, therefore it is hardly going to be a whacking great "sail" to catch the wind. I am much better equipped and experienced at working with timber and as access to them will be straightforward without ladders they would be easy to keep an eye on and repair if needed. Some while back I has a similar conversation with the structural engineer we regularly use. His opinion was that although hardly anyone uses timber it is mainly because steel and or Ally are more resistant to weathering or rotting and less variable as built onsite. OTOH he said anyone nervous about timber should consider that most systems are mounted on a timber framed roof in any case.

I have to say I am tempted to go for it.

Desp

[Joeboy]

Thanks Nowty, I measured the wall thickness at .84mm but I know there are variations in pipe thicknesses, I may even triple it as I do like OTT when it comes to this kind of stuff.

It has actually been quite good being quarantined with Covid, last tuesday til thursday were pretty bad but since then I have been able to potter about the place with a tape and notebook working out a plan for all these shenanigans

I am seriously considering mounting six panels up on the lofty flat roof on a timber framework, they will be lifted up by 25cm at one edge so basically at less than ten degrees inclination, therefore it is hardly going to be a whacking great "sail" to catch the wind. I am much better equipped and experienced at working with timber and as access to them will be straightforward without ladders they would be easy to keep an eye on and repair if needed. Some while back I has a similar conversation with the structural engineer we regularly use. His opinion was that although hardly anyone uses timber it is mainly because steel and or Ally are more resistant to weathering or rotting and less variable as built onsite. OTOH he said anyone nervous about timber should consider that most systems are mounted on a timber framed roof in any case.

I have to say I am tempted to go for it.

Desp

Nothing wrong with that if you effectively treat the timber and inspect every year. I always liked the deep bucket multiple washover/soak of timber to get it taking in as much inhibitor as possible. One of my arrays is primarily on timber but I did use ally rails at the end for the non flexing clamping force of the panels to the ally via rail designed brackets. Easy to go your own way as can just drill right thru the face of the panel edge and screw down to the timber. I would use s/s screws and load spreading s/s flat washers for that.

[nowty]

I love timber too and especially fenceposts.

Easy to source, easy to cut to get whatever an angle you want with a mitre saw, a few galvanised coach screws and.......................

[Stig]

One of my arrays is primarily on timber but I did use ally rails at the end for the non flexing clamping force of the panels to the ally via rail designed brackets. Easy to go your own way as can just drill right thru the face of the panel edge and screw down to the timber. I would use s/s screws and load spreading s/s flat washers for that.

Won't you get galvanic corrosion with s/s and aluminium?

[Joeboy]

One of my arrays is primarily on timber but I did use ally rails at the end for the non flexing clamping force of the panels to the ally via rail designed brackets. Easy to go your own way as can just drill right thru the face of the panel edge and screw down to the timber. I would use s/s screws and load spreading s/s flat washers for that.

Won't you get galvanic corrosion with s/s and aluminium?

Can rubber Bush it to isolate while giving extra grip? I don't have enough experience with galvanic corrosion on surface, mine was all sub sea.

[Oldgreybeard]

My fix for galvanic corrosion with stainless and aluminium is to use nylon top hat washers, sized to fit the hole in the alloy part and also fit the bolt. This is an example, an alloy panel clamp that is fitted with a top hat washer and stainless bolt:

Panel clamp 1.jpg (53.17 KiB) Viewed 2125 times

Panel clamp 2.jpg (79.59 KiB) Viewed 2125 times

[spread-tee]

One of my arrays is primarily on timber but I did use ally rails at the end for the non flexing clamping force of the panels to the ally via rail designed brackets. Easy to go your own way as can just drill right thru the face of the panel edge and screw down to the timber. I would use s/s screws and load spreading s/s flat washers for that.

Won't you get galvanic corrosion with s/s and aluminium?

I dunno....

The Navt***n vacuum tube systems used a frame constructed out of both alloy and S/S parts and used S/S bolts to hold it all together. Ours was up there for ten years before being dismantled to build the lofty etc, it all came apart with no signs of corrosion and now is all back up there with all the original equipment and bolts etc.

Desp