My home made solar panel

My current project is creating my own solar panel and eventually an off grid electricity generation system.

For me this project may be a little out of my league, my main aim is to not burn anything, blow up anything and not to get hurt (I seem to end up doing one of these somewhere along the line). As for the secondary aim, that is to set up the shed with a little self contained solar power system. It should, with a bit of luck, power any lights in the garden and various pumps / fans etc I have planned for other projects.

I have a little background in electrics, I know how to change a plug and not kill myself, but creating a solar panel is something way out of my comfort zone.

I got some info from these guys to help me along as I was so far out of my depth.

You know what!? it’s not all that hard! Well not hard in theory, I guess there is a big difference between watching and reading than actually doing.

So here goes!
I managed to source some solar cells off ebay. They were seconds that hadn’t passed quality control but were not broken. They mainly failed due to staining or the solder tabs are not 100% on the back. I would avoid the cracked ones as the fully formed ones are brittle enough as it is.

None of these cells had tab wires attached so I needed to find some tabbing wire. Tabbing wires are long flat solder wires that run along the front of each cell to connect them to each other. I sourced some tabbing wire again from eBay, it turned out I sourced rather a lot! I guess it will be handy for the panels on the house!

I’ve opted for a 24 volt panel as one of the pieces of equipment I have is rated at that.
I’m going to create a smallish solar panel, as I don’t want to use up all of my cells in one disaterious learning project. I decided on 12 x 4 solar cells which at 0.5v each should give me around 24v (fingers crossed). This should give me, at the rating specified, 86 watts of pure sun power!!! This should be enough to power my lighting as it will be LED and a little left over for projects. If this works out I will be adding more DIY panels, so if I run out of sun power it’s no big deal.

I sourced some board which was more than big enough for my needs, it will be cut to size when I’ve traced on the cell design. Next I created a template for one of the cells out of thick card and started penciling in my cell layout on the board. This is where I made my first mistake, I forgot to leave a gap between each cell. A quick adjustment and my masterpiece was complete. If only the actual build was this quick and easy, everyone would be going solar.

I cut the board to size and went for a cup of tea  :)

Now this is the tricky bit! and the bit where I will probably fail my main aim and get burnt!
Each tabbing wire needs to be long enough to join to the next cell, so they should be twice the height of the cell. I wrapped the tabbing wire around the card template many times and cut the wire along one edge, which gave me lots of wires the correct length with the minimum fuss.

This is the painfully slow bit until you get better at it. Each tabbing wire needs to be soldered to the front of each cell, not just in one or two places but the full length of each of the vertical solder lines. You will need some solder, lead free unless you like to poison yourself, and a flux pen to help the solder flow along the solder lines.
I broke many of the cells to start with and got very frustrated. I started to wonder if this was why people didn’t make their own panels. But slowly I learnt how to handle the cells and how not damage them during soldering, not before a good ten went in the bin however.

Tip: Do not leave the soldering iron in contact with the cell surface for too long, or the cell will overheat and fracture. Use the flux to help the solder flow quickly and at a lower temperature.

It took a while to solder up the tabbing wire to the cells, I did a stint of 12 a day which took about 45 mins per day. I like to break big boring jobs up into small daily amounts.

To hook up the cells together the tabbing wires leading from the previous cell need to go under the the cell below and soldered to the points on the back, creating a chain of cells.
I made initially a chain of three before testing each with a multimeter. Once I became confident that that I was building the chains well I graduated to building a chain of six before testing.
It didn’t take me all that long make all eight chains, connecting the cells together is a lot easier than soldering the tabbing wires to the front.

To mount the chains to the board it’s a simple process of either placing a blob of bathroom sealant on the back of each cell, or in my case take the easy way and squirt a couple of lines of sealant down the board and place the cell chain upon it. Finally I connected up all of the chains in a long snake and tested the panel in bright sunlight. My multimeter read 27 volts, which was more than I expected but I guess these things vary a little. Hopefully my equipment can deal with this difference.

My half complete home made solar panel

To finish off I cut some edging strip which gave me a nice lip to place the glass upon. I thought I should seal the edging strip and the glass to try and make this panel as weather proof as possible. I think I may have trouble with water getting in as this project has been a little hastily put together. I guess I will find out in good time.

The current state of affairs is that due to the house move my solar panel is in storage, I’m hoping it’s going to to come out of the other end ok as these things are very fragile.

I have purchased a 10 amp solar controller from eBay which as far as I understand connects the solar panels and the two car batteries I have sourced together. If the system is not under load the solar panels will trickle charge the two batteries ready for me to use the energy when I want. It has a short safety cut off which it great because if any of you, like me, have shorted out a car battery with a jump lead you will know how much energy these things can produce in a short time. A fire hazard for sure.

As soon as I’m in the new house and the shed is setup, I will hook all of these components together as see if it all works. But as for building your own solar panels, I wouldn’t say it was easy but I see no reason why you couldn’t make you own especially when you save so much money over the retail ones!

As ever let me know how you get on, I’m happy to answer any questions.

Jason

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