DIY lecky

[dave45]

The finished panel - on its fateful full-sun test in the DG unit.... note the less-than perfect condition of the remaining cells. I had repaired some of the weaker/smaller spare cells with even more broken bits wired to that cell in parallel. Messy and inelegant, but the improvement to the weak cell was magnified 36 times so it was worth it. (If all the other cells could give 2.5 amps and the weak one could only give 2.2 amps, the whole array gives 2.2 amps, so augmenting the weak cell with a 0.3 amp fragment brings the array back up). Table-lamp and digital multimeter were invaluable for this. So there it was nicely squirting 2.5 amps or so into the battery.


And here is the side of the DG unit afterwards... The nicely sealed unit is converted by autumn sunshine heat into three separate layers - glass/plywood/glass. :-(
I wanted to cry. My master plan was a failure. Weatherproof it was not.



But here is a VERY good use for a solar panel.... Why? As well as being free energy, you remember that 18volt/12volt discussion? The higher voltage does wonders for a scalextric car.... be careful not to burn them out though !

[dave45]

These are another type of solar cell/panel, called "amorphous" cells. They have an interesting property in that current is along one axis and voltage another. The narrower dimension is scored by lines half an inch apart, dividing it into long-dimension strips. Each of these is half a volt, and the current depends on the length of each strip. This comes in useful when your kids break them !
The whole thing looks like a sheet of glass, and you can cut them with glass cutters (i.e. badly). What have you got to lose when your kids have busted them?
Also I have found them to be useless... I was using them for scalextric when they just failed in full sun. They were bargain-bucket things though. False economy again methinks. So I bought a mounted one, allegedly perfect. That failed too after a few months. These are the most popular type of solar technology in smaller-scale panels/cells, i.e. in all garden and car equipment. Serious solar kit uses the separate, more flimsy blue "crystalline" cells.

My next plan was to use a double-glazed scrap patio door that I got from a mate, and insert my home made panel PLUS some of these amorphous panels to fill up the space... BUT to keep the aluminium surround fitted so that it couldn't melt apart. Then I found that
a) the amorphous cells were rubbish and
b) that there is a large amount of "sag" in the middle of a patio door glass and I couldn't see how I was going to get my homemade panel inside it with the friction damaging the flimsy cells. I could only have done it vertically I guess, to eliminate this sag.

So rather than risk yet more 5h1t happening I decided to buy some commercial units.
I have some pics if you want to see the construction of those :-)

[tiggy]

Dave45 I will come back to this and add some info about using solar panels on canal boats and the few experiments I have done at home with small panels but I should be tidying up the back yard this very minute, back after hard labour. regards Tiggy.

[tiggy]

I started out with a small trickle charge panel off the internet,this was intended to stop the battery in my van being flattened by the alarm because it was only used once or twice a week.The 1.5watt panel was a bit small but ok for my husbands car as it had no alarm . Van still needed a panel so I bought a 4.8 watt panel on special offer from Maplins,this does the trick and I managed all summer with a very dodgy battery until I got a better one out of a scrap car.Think me and van are now sorted. I bought one of Maplins solar briefcase things but it wasnt brilliant on construction and when it packed in I had my money back.That however did charge well and the regulator worked ok.I also have 4 of Maplins smaller trickle charge panels which have been outside all winter and still work. 1 is keeping the engine start battery on my canal boat topped up the other 3 are keeping spare batteries topped up. I also got another 4.8 watt panel to keep 2 cabin service batteries in good nick on the boat. These small cheap panels are doing the job I bought them for ok so far.
Expensive panel bought to supply a usefull amount of charge while on the boat and moored somewhere [saves having to run the engine just to charge batteries] broke,I know not why . Any way it went back to the shop [not Maplins] and was replaced . Iam still not sure what to do about a panel for the boat so have not bought any more.Will use the 18watt panel and regulator for a home project.
Think solar has definatly got its uses but needs to be carefully matched to the task.The canal boat is a classic "off grid" situation , my liveaboard friends find that between 160 and 120 watts worth of panels are needed to supply most needs in the summer and a usefull amount of charge in the darker winter time.Hope this helps .Best wishes Tiggy

[JayBee]

Nice work Dave!

You can get aluminium U-channel from B&Q and any size you ever wanted from various eBay suppliers. The U-channel can then go around your panels as framing.

I started out making a panel with broken polycrystalline cells but there are plenty of ready-made monocrystalline (more powerful) panels cropping up on eBay for about £2.75 per watt so I bought 5 20W panels for £275.

I have downsized and use a lot less electricity than most so this 100W system is more than enough for me.