You will find little tabs on the back of the cells. Take your soldering iron and heat it up. Touch the tip to the tab and gently feed some solder onto the heated surface of the iron. Just one drop will do. Make sure you do all 4 or 6 of the tabs that you find.
The tabs on the backs of the cells will form a line, one on top and one on bottom. The top tabs are negative and the bottom tabs are the positive leads. With the drop of solder on the backs of the tabs gently place a copper wire lead onto the tab and heat it up. The wire will bond to the tab and connect the negative tabs together. Do the same for the other tabs.
Use different color wire for negative and positive leads to avoid confusion.
The cells are now stuck down to the plywood base in the pattern that you made before and the wires are gently fed through the back of the plywood.
Use just enough caulking to secure the cell to the backing. We usually use some sort of silicone because it is pliable and lasts a long time too.
Use each hole for 2 cells, one facing left and one facing right so the lead wires will easily thread through the holes. Be careful to not press too hard on the cells when you are attaching them. We usually use a small piece of wood to place on the cell to press evenly with, thereby avoiding any breakage.
When you have all of the solar cells stuck down on the backing you will need to wire all of the same color (negative) wires together.
It is a good idea to make the leads long enough to join the ends later. Test fit a couple of cells before you begin.
Remember to connect all of the positive leads together and all of the negative leads together or your panel will not function properly.
This spaghetti of wire will get connected to a junction box outside of the panel. We have started to put another piece of plywood on the back of this backer piece just to keep out the weather. Remember to coat it with 3 coats of epoxy too.
All of the same colored leads will be joined together and the positive and negative leads will be connected to just one wire leading to your batteries.
Use the glass to cover the front. You can either use aluminum sealer strips that you can screw the glass down with or make your own from wood. Seal up all the edges and leave a drain hole in the bottom of the panel to let any accumulate moisture drain out.
Once your solar panels are up and running, the next obvious requirement is some sort of charge controller, since continuous overcharging will ruin the expensive battery bank.
Charge controllers intended for solar panels work by monitoring the battery voltage, and once it reaches full charge, the controller simply shorts the solar panel leads together. This doesn't harm the solar panels, but it does waste whatever power they're generating. The energy ends up heating the transistors in the controller instead.
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