Building the Solar Powered Wall

Some of the gear I ordered for the new garden shed has arrived, so I got to work on building my power wall. 

Wall frame:

The first step was to clean up an old steel and aluminium framed table on castors that would provide the base and would keep the batteries up at a reasonable level. 

The table frame had been outside for some time with no top. It was in reasonable condition but had some surface rust. The castors were worn, and had pins welded to the base. 

I initially stripped the rust out, applied some Rust Eater, then later a matching primer. Finally I sprayed the bulk of the frame with some black Rustoleum paint. 

I then removed the castors with an angle grinder, painted the bottom of the legs and allowed to dry. 

The frame itself had a single piece of aluminium tubing and a compromised piece of laminated board holding the sides together. I added and additional brace across the rear bottom made from the same sized aluminium tubing, allowing me to remove the laminated board.

At this point, the frame seems sturdy again, but looking at the top I decided to add an additional brace. The top when I put it on will be sitting along two runs of aluminium tubing far enough apart that I was concerned about how it'd support the weight of potentially 3 batteries, so I decided this was appropriate. 

The wall:

When my last Bunnings order arrived (as opposed to the first which I'm still waiting to have delivered), an 1800x600 pine panel came as part of it. I knocked 100mm out of it given this will be in the lowest part of the garage and will quite likely with the flooring be a tad under 1800mm high. 

I then screwed it into the back of the frame. Fairly straight forward.

The breaker box:

A simple 8 pole enclosure is all I've used - 5 x 63A circuit breakers that are really intended just as switches, 1 RCD for the 240v side, and a 240v power meter. 

I put that up so I could start putting wiring into place as components arrive. 

The inverter:

My 2000w inverter arrived yesterday so that wound up on the board and was wired in. 

Connections:

One of the biggest issues with this wiring is the cable size. Everything is being wired for 50A+, so the cable is difficult to work with. 

One of the biggest issues I had with the use of breakers is that they're all single pole and I needed a way to rationally deal with connecting together really thick pieces of cable for the negative side. The few options that exist for joiners are either clunky or expensive. 

In the end, I simple decided to use Anderson plugs. This allows me to modularise everything and really isn't that expensive. Each breaker effectively has an "in" and "out" socket on the rear of the board with the negative side wired between them. 

There is one junction for the negative side - using an old gold terminal from a car sound system that's been in my tool box for the past 20 years. That one allows me to take the negative side of the battery load circuit and split it to the battery protector, inverter and the powerpole circuits. 

I probably could have simplified the whole thing further, but the Anderson plugs are easy enough to work with and heavy duty enough that they should handle a bit over 50A - not that I ever see it hitting that kind of load. 

Up next:

The MPPT controller isn't here yet, so I can't finish tying all of the cabling together. 

The battery protector isn't here, so I can't sort it out either. It's effectively just adding a positive loop going from a breaker that cuts it power, that comes back to the breaker and feeds two circuits (inverter and powerpoles). 

....and I'm awaiting on a couple of 3m runs of 8 B&S cable to finish wiring it all up and getting the battery connectors installed.