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A good transition to a question i have please. I already know about the amps staying the same but with my method, you essentially can configure a great "little" battery charger for any voltage battery. I'm not talking off the grid applications here for me only charging batteries to be used in a battery generator i've made. Any real-time power that the panel made would only run something very small in current.
Question: When a solar company advertises an average amp rating for a solar cell let's say @ average 3.6 amps per solar cell, why is it that i can never achieve that or even come close to it when i expose that solar cell to direct sunlight? I'm lucky to get .200 mA give or take. I think what the advertisements are really saying is that the solar cell is capable of handling up to an average 3.6 amps, if configured in parrallel with more solar cells or another solar panel. I don't think it's saying that the solar cell itself will produce that much current. What say you.Comment
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How are you measuring the current from the cell? Some cheap ammeters might drop as much as .5 volts when measuring DC current at full scale.
You would not expect the full 3.6 amps since the measurement conditions are not realistic in terms actual light available. But it should be within 75% if the cells are good, honestly rated and correctly installed. And properly measured!SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Well, I'm measuring the current from the cell with a multimeter (cheap yes). It tops out at .400mA. I use B grade solar cells from ML Solar which actually appear to be in great shape, better than they advertise them to be. I've built 6 solar panels, purchased pre-manufactured solar panels, and exposed them all to the most direct and potent sunlight i can with the same results each time. I never do see the 3.6 amps. Possibly I'm reading my meter wrong but i doubt it? Possibly B grade cells just suck? Curious if you've ever seen anything over 1 amp come from one 3x6 solar cell?Comment
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What I was getting at was how are you physically making the connection from your multimeter to the cell? If there is a ten amp range, most meters require you to plug one of your meter leads into a different jack on the meter as well as to set the range switch properly.
Then just connect one lead to the + of the cell and the other to the -. If that still does not work right, check for a blown fuse inside the meter. (Often in the battery case.)SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Panel Output
I hope it's understood that if a 1/2 volt 3.6A cell is cut in half, you could get
1/2 volt at 1.8A from each. Parallel them to restore the original output,
series will give 1 volt at 1.8A.
In building a panel of some size, it's my experience that some cells may
be damaged and restrict the total output. One way to find them is connect
a shunt or 0.1 ohm resistor across the output. Since I = E/R, the voltage
across the resistor, divided by 0.1 ohms (or multiply by 10), gives the
(nearly short circuit) current. 3.6A reads 0.36V.
If current is way down, measure the voltage across each individual cell,
carefully observing the polarity of each cell. Good cells will likely show
1/2 volt, bad cell(s) will show REVERSE POLARITY voltage, perhaps as
much as all the good cells combined. When the worst cell is found, short
it out and measure panel output current again. If it's still way down, test
again for the "next worse" cell. I run panels with a cell or 2 shorted, some
may want to try and replace the bad cell(s).
With lots of cells the test could start finding the worse column of cells, then
narrow it down to a specific cell. I showed a tester to automatically do this
on a thread in 2012. Bruce RoeComment
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It's a Crystal. So cut it as one?
The vibrations from a Dremel by themselves will shatter it unless they're damped. That's why the guy who embedded them in epoxy was getting away with it. I don't think you could get a Dremel steady enough freehand. If it was me, I'd be thinking tile saw.....Comment
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Jaiman
Was just reading your idea and thought maybe this is worth a try lay a piece of very hot straight copper wire along the line where you want the break and allow it to sit for 25-30secs and pour some cold water on module and if it reacts like glass it should crack along the line of wire(try on scrap first maybe) we used to take tops off beer bottles for electric fence insulators this wayComment
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but the most i can divide one cell is in 6 different sections to get 3 volts. Current is yet to be known exactly but i can guess.
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