I made my 180 watts solar panel today.
It produces under 80 watts actually. You need nice sunny day and you have to let sun rays hit directly to panel if you want 100% efficient. I spend 60 dollars to cells. each cell 5 watts. There are 36 cells. Each cells 0.5 volt also. So I made 18 volt solar panel but why?
18 volt required to charge 12 volt battery, however I use my panel to connect grid tie inverter.
I bought 1 kg epoxy for 10 dolars. Encapsulation for 30 dollars. Bandage and other soldering stuff for 10 dollars. It is nearly 100 dollars and a lot of time with low cost metarial. If I bought 150 watts better quality encapsulation panel It would cost 120 dollars.
So it is better to but I think.
Congratulations, I like it when people make their own solar panels. But, they usually do not get the best results. The problem is usually that they mix solar cells with different curves of the characteristic current voltage. If the difference between the cells is very large, and that always is, your solar panel will work for a few years.
The other problem is that the front glass has to be iron free. If you do not have such a glass it is best to leave it unprotected because you will lose much of the important radiation if you use ordinary glasses.
My best wishes that it works perfectly ....