During in the week I discovered that my rack side had bowed during welding, really didn't expect that that to happen as the welds aren't that big. These sides need to be parallel for the drawer system to work. Currently I have the side G-clamped together with the tops and bottom spaced out, so past the point of being straight, hopefully this will work. Other option is to warm them up and straighten that way. I could also put flat bar across the front and rear to control the width.
Yesterday I had almost a full day at work, so made some good progress.
There are sixteen lengths of angle which forms the slopes of the mounting system that the panels will be clamped to, I've put three M8 stainless steel rivet nuts in each one for the panel clamps, so another 48 holes, and manully setting 48 rivet nuts, luckily we have a decent tool.
I cut all the sides of the trays with my mitre saw - not the hand saw in the picture, it just happened to be there.
I also had to drill eight holes in each side piece, so another 64 holes for the M5 screws the drawer slide.
First tray assembled, its pretty critical each tray is the same width, so I need to be extra careful there. I would have loved to have welded these, but I don't have a TIG welder, and I've never TIG welded, so 6.4mm ally rivets it is.
The tray feel very sturdy, 25mm x 6.4mm equal angle, and a 5mm base, mind you they will be holding over 85kg of cells, so they need to be sturdy.
I've ordered a 400 amp and a 250 amp T class fuse, and appropriate holders, also I've ordered a 40 x 8 x 1000 tinned copper bar to make my busbar.
On a very important safety note, I've learnt that a lot of DC breakers are directional, wire them up wrong and
this can happen which is not good! In a solar storage system there is only one place where you can use a directional breaker, and that's between the MPPT and panels. You would think you could between the MPPT and busbar, but if there is a short circuit fault in the MPPT then the current is going to flow from the battery into the MPPT, so this needs to be bi-directional, as does the main battery breaker, if you are to use one. So I'm not going to be using what I've purchased so far. The directional breakers are referred to as polarised, the non directional are non polarised, it is non polarised that I need, and they need to have the correct voltage rating as well, at least 60v DC, a lot of stuff is rated at 48v or less, which is no good. It's all to do with the ability of DC to sustain an arc, AC passes throgh zero volts at 50Hz so self extinguishes, DC does not and when you've got cells capable of passing circa 20,000 amps in a dead short you need to do it right.
I have found some suitable Noark breakers, but they don't appear to be sold in the UK, so I need to email a couple of overseas suppliers to see if they can ship them here. Other option is to just use fuses - I was going to use fuses and breakers, breakers giving the easy option to turn stuff off, but I now know what goes on when you turn something off under load.
It seems very difficult in this country to buy the correctly rated breakers, and whilst there is China I'm now not confident of what can be purchased from there - one supplier told me the breaker I'd purchased could be wired either way, but it is very clearly shown on the breaker that it is only to be wired one way, and therefore is not bi-directional.
