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Author Topic: How do you build a home-made solar panel?  (Read 4072 times)

Offline MSULLI8

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How do you build a home-made solar panel?
« on: 24/09/2008 17:47:57 »
I've been looking into making part of my house go to solar power so i started to do some research into solar panels. I wanted to try to make something small work off of the panel before i started to go to a bigger scale and I recently bought some broken photovalic solar cells and wired them all together, soldered them up and such and ended up putting out 9-10 volts. I decided that i would try to light up a small 3 volt bulb by running the panel to a regular 9 volt battery and then from the battery to the bulb. Well to make a longer story a little shorter, the battery dies in just 10 minutes. It never gets recharged from the solar panel and I cannot figure out why. If anyone can throw some theories at me it would be appreciated. (the panel does have a diode in it to prevent battery discharge)
« Last Edit: 27/09/2008 10:37:01 by chris »


 

Offline peppercorn

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Re: How do you build a home-made solar panel?
« Reply #1 on: 24/09/2008 19:30:32 »
Firstly, a 9-volt battery would almost certainly blow a 3V bulb.
Are you sure the bulb is 3V?

Second, are the solar panels rated in any way?
Is there any indication on the packaging what current they will develop in direct sunlight?

On the battery side: Is the cell lead-acid? If so you will probably need additional voltage to get it charging. For example, a lead-acid car battery will require about 14V to take charge - due to internal resistance.

Another thing is if you're measuring a solar panel with a volt-meter but unloaded the voltage may appear higher. You ideally need to measure the voltage generated with a load - that 3V bulb should do...
 

Offline techmind

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Re: How do you build a home-made solar panel?
« Reply #2 on: 24/09/2008 22:12:10 »
If by "regular 9V" you mean something like a PP3 (alkaline?) then firstly you shouldn't be trying to recharge a non-rechargeable alkline anyway (it'll go "pop" after about 1 full charge - at the rate of a solar-charger, this probably won't be dangerous, although it might make you jump!).

How big is your solar panel, and how much sun have you got?
What's the voltage and current-rating of your bulb?

My gut feeling (even assuming the right volt/current combination) is that you'll need a solar panel of 4x6 inches absolute minimum to light even a fairly modest torch bulb from strong sunlight.
If your panel is smaller than this, then energy out > energy in, so your battery would go flat anyway.
 

Offline techmind

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Re: How do you build a home-made solar panel?
« Reply #3 on: 24/09/2008 22:59:46 »
I've been looking into making part of my house go to solar power so i started to do some research into solar panels.
If you're in the UK then it's the wrong time of year to be thinking about "going solar"! In any event, you might be better off with a solar-thermal technology (as simple as a coil of cheap copper pipe painted black and covered with a transparent cover) - although it's disappointingly low-tech!
 

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Re: How do you build a home-made solar panel?
« Reply #3 on: 24/09/2008 22:59:46 »

 

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