Author Topic: Solar Cells - How to connect?  (Read 677 times)

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Offline hoosier122Topic starter

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Solar Cells - How to connect?
« on: November 30, 2011, 02:40:17 AM »
So I bought these cells on Ebay for basically nothing. They are far too brittle to be soldered directly together. How would you connect them? Would it be best to use an insulator to back them like a thing piece of wood or cardboard?

How would you protect them? Plexiglass? Would a simple clear epoxy block a significant amount of the ultraviolet rays?

I have about 50 of these cells, so I should be able to get some decent voltage out of them...although I haven't decided on a specific application.

Blue is the face, silver is the back.
« Last Edit: November 30, 2011, 02:47:38 AM by hoosier122 »

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Re: Solar Cells - How to connect?
« Reply #1 on: December 01, 2011, 05:58:04 AM »
How would you connect them? Would it be best to use an insulator to back them like a thing piece of wood or cardboard?
yes, definitely do that

Quote
How would you protect them? Plexiglass? Would a simple clear epoxy block a significant amount of the ultraviolet rays?
I wouldn't bother too much protecting them. But yea, glass is best. You can get various transparent materials and measure with a multi-meter if any block light.

Quote
I have about 50 of these cells, so I should be able to get some decent voltage out of them...although I haven't decided on a specific application.
You aren't going to get much current/voltage out of them, at least not enough to power anything more than a mcu and some LED's. Maybe a low power sensor or few.


Personal opinion: free stuff is great, but a solar panel powerful enough to do useful hobbyist things will cost no less than about $30 with today's technology. A year ago I bought a $3.50 solar panel to play around with. It was rated at 1W and sized at 75mm x 100mm. It generated enough current/voltage to power an Axon Mote and ~3 LEDs, and that's it. The solar panel would need to be 10x bigger to power a single motor . . .

Offline hoosier122Topic starter

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Re: Solar Cells - How to connect?
« Reply #2 on: December 01, 2011, 02:21:38 PM »
So how would you connect them? Yes, I realize they aren't going to be able to power much more than a few LCDs, but I really just wanted to experiment with solar from the ground up.
« Last Edit: December 01, 2011, 02:23:07 PM by hoosier122 »

Offline Soeren

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Re: Solar Cells - How to connect?
« Reply #3 on: December 01, 2011, 04:34:55 PM »
Hi,

So how would you connect them? Yes, I realize they aren't going to be able to power much more than a few LCDs, but I really just wanted to experiment with solar from the ground up.
I'd put some Mylar foil or similar on a fairly rigid aluminum plate and then glue the cells onto the Mylar with some RTV silicone.

For the connections, conductive epoxy (Liquid Wire) will probably be the easiest solution (you paint it on). For higher current, use eg. 2 or 3 strings of series connected cells (plus a Schottky diode in each string), then parallel them for higher current.

On top of this, a piece of 3mm acrylic or polycarbonate (glass filters out a good deal of UV, so makes them less efficient) will be good protection. When completely assembled, add RTV around the adge to mount and seal it, but keep a few holes at the bottom for ventilation.

When you paint the conductors, make them wide and short (mount the cells close together) and before you paint, install some terminals to paint onto - spade terminals would be a good choice - don't solder to a terminal that is "epoxy wired", or you will harm the "wire".

You can get this epoxy from some electronics stores, but auto accessory shops carry it too, as it's used to repair broken rear window heater wires.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
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Re: Solar Cells - How to connect?
« Reply #4 on: December 01, 2011, 09:23:03 PM »
On top of this, a piece of 3mm acrylic or polycarbonate (glass filters out a good deal of UV, so makes them less efficient) will be good protection.
hmmmmm the solar panel I bought has a glass cover on it . . .

Offline Soeren

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Re: Solar Cells - How to connect?
« Reply #5 on: December 02, 2011, 02:51:16 AM »
Hi,

On top of this, a piece of 3mm acrylic or polycarbonate (glass filters out a good deal of UV, so makes them less efficient) will be good protection.
hmmmmm the solar panel I bought has a glass cover on it . . .
Quartz glass no doubt. Regular "window glass" is too "lossy" and that's what most people are able to get.

How lossy will probably depend on the exact chemistry (and thickness of course) of the glass, but I don't have any numbers for it and unfortunately no UV sensors to get any exacts.

It should be easy to get a relative measure with two identical cells, some different glass and plastics.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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