Using battery powered light source for solar panel demonstration

[Emily Flynn]

Hi!

As part of a college project I want to be able to demonstrate solar energy to kids using a mini solar panel. I have attached a little sketch so you get an idea of what I want to do.

The solar panel is about 100mm x 70mm and will generate only just over 1V when stuck in front of any of the halogen lights in my house including 800W heater. I have a little motor I want to use the panel to power, and it will work up to about 150mm away from a halogen bulb.

Now the thing is, to create the illusion of solar power, I want to make a little sun shaped object with some bulbs fitted into it and I'd prefer it to be battery powered, but I am gathering this is going to be tricky as I don't want to have to use one of those big chunky batteries.

Any ideas on how I could go about this?

Thanks in advance

Emily

 

[NorthGuy]

How about the real Sun? It'll give you way more energy than lights would.

How many cells does your panel have? Each cell will give you about 0.6V in full sun.

 

[Emily Flynn]

Hey thanks for your reply. I want to be able to use it indoors so the real sun I cannot use, even though it is obviously the best energy source. I've attached a pic of the little panel I have as I actually know nothing about it - I got it from a little edu-pack that had no info on it. It is probably madly outdated, so maybe there are newer versions I could use that would be more sensitive to a lower wattage bulb that could then be powered by a manageable size battery?

 

[NorthGuy]

Hard to see, but it looks like it's either one or two cells, so it's normal voltage should be either 0.6 or 1.2V. If you get 1V, I guess it's 1.2V. Actually the important thing is the current. I guess you can get about 1A @ 1V.

You need to experiment. A bright modern LED flashlight should produce the same as a small halogen bulb. The ones that you wear on your head are very compact and can be made to emulate the Sun. But it's impossible to tell if it's going to work without actually trying it.

 

[Emily Flynn]

I just grabbed a disused battery powered LED lamp that has a 16 bulb array working off 6xAA batteries, I put batteries in it robbed from various remote controls around the house, and I got @ 700mV putting the light pretty close to the panel. That is certainly promising. I had a quick look on my local DIY stores website and they have a 'Super Bright LED' worklight that uses 4xAA batteries for a 72 LED array and it cost 10 euro which seems pretty decent. A trip to the store tomorrow so! I'll get my hands on a better mini-panel too I think. Thanks a million for your advice, I hadn't thought LEDs would work at all so had discounted them really.

 

[NorthGuy]

The voltage alone does not mean much. Even insufficient light will put it way up. You need to test if it gives you enough current for the motor.

You can buy a panel on e-bay. The bigger the panel, the more energy you get from the same light source.

Sun, even through the window, will work the best.

 

[Nigel Goodwin]

If you ever watched the robot schools competitions a few years back one event was solar powered car racing - you wouldn't believe the massive amount of lighting they had over the track in order to simulate the sun.