So in order to save some money, I decided to build my own solar panel. So far I have built the frame and souldered 6 rows of solar cells, each with 9 cells. I have been having an issue with finding directions on how to wire them together. Do I want to connect the cell rows in series or parallel?
It seems to me that I would want to wire them in parallel but I am concerned that if one of the cells goes out I will lose all the power generated by the cells behind it, but this is how I've been seeing it done it most of the videos I have come across. Can anyone help me out with this? Maybe someone who has built a panel themselves could post up a picture or two of the wiring or explain how they did it?
Any help is appreciated. Thanks!
Well, I pulled it off. I separated the 0.5V solar cells in to two groups. Each group was wired in series and consisted of 3 rows of 9 cells each. The two groups were then wired in parallel. I did this so that if one cell or section went out, enough voltage would still be produced to charge the 12V deep cell battery.
After soldering the cells together in the rows, I attached them to a thick plywood board that I had previously covered with a white, UV-protectant paint. Once the cells were attached using a dollop of silicone in only their centers to account for expansion and contraction of both the board and cells in various weather environments, the rows from each section were then connected in series by soldering tabbing wire. Both sections were then connected in parallel with the same copper wire that one would find in a solar output cable and a blocking diode was added to the positive wire inside the solar panel to prevent the backward flow of power at night or in less than ideal sun conditions.
Everything from the solder joints to loose wiring withing the panel was stuck to the board with silicone. I cleaned off the solar cells themselves with glass cleaner. A thin wood frame was placed around the edges of the board upon which I attached a 1/8" thick piece of plexiglass which seems fairly durable and recently survived a hail storm. The frame also has a few small holes drilled in the bottom to equalize the air pressure inside the panel and allow for condensation to run out should it ever gather in there. The outside of the panel where the wood and plexiglass connect were coated with silicone to prevent water from getting in.
A test with the multimeter showed me that power was indeed flowing so I connected the positive and negative wires that I had left hanging out through a hole in the bottom of the panel to the solar output cable.
Wow... very inspiring. I'm giving serious thought into turning my entire RV roof into a giant solar panel. How time consuming is soldering all of the tabs? From the little I've read, it seems like a big deal. If I were going to completely cover the roof of my 20' RV with cells, could I do all that tabbing in a day?
Unbelievable! Nice work. And I don't know what bus wire or tabbing wire are so you're well ahead of me.
Wow... this is really fascinating. It would be awesome to make a totally custom panel to completely cover the weird space left on the RV. How many volts / watts are each panel? My guess is that clusters of them are in parallel, and then those clusters are wired in series. Just a guess, though.
This is actually the main reason why I keep going back to creating a custom Sprinter based RV, so I can maximize roof space with standard solar panels, but maybe customizing the solar panels may be wiser...
This is stuck in my head now because I think it'd be awesome to blanket the top of an RV in solar cells that are completely flush... one complication I just realized is that full panels are rated in the impact they'll withstand - most can take a 1" hailstone at 50mph. You'll have to think about what you're going to cover these with that will protect the cells - if not from 50mph 1" hailstones, which is admittedly kind of insane, at least from general shit hitting the roof. I just got my panels today and those cells feel super, super fragile (I'm actually surprised how much the panels feel like super thin IKEA floor mirrors... I kind of can't believe these things don't just explode at highway speeds with the wind and bumps!!)
Yeah, count me as super-interested in how this goes, too. And yeah, seems like you can figure out how to wire them by taking the voltage range for one cell, let's say it's 2-5V (random guess) and then look at your controller's input range, maybe it's 30-80V, so that means wire them in clusters of about 15 in series (2*15=30, 5*15=75) and then wire all the clusters together in parallel, which sums amperage.
I think I understand this well enough to say: let's say you had 100 cells each producing 2-5V and 0.15-0.25A, to be simple about it, and your controller takes 30-80V and up to 480W.
You'd wire clusters of 15 cells in series so each cluster produces a voltage range of 30-75V, and then you could use up to 25 of those clusters in parallel (480W/75V = 6.4A, 6.4A/0.25A = 25.6) without risking overloading your controller.
I think that's right, anyway... but I'm a total novice at this stuff so don't take my word for it!