We spent pretty much all day yesterday, trying to drain the power from a couple of batteries, so we could try recharging them with our small solar panel, in the hopes of powering our solar scribble-bot more efficiently.
Naturally, in order to charge a battery, we needed a battery without a charge. We also wanted to get a feel for how long a fully charged batter could run one of our hobby motors, so we could compare it to how long it ran once charged with the solar panel. To accomplish this goal, we set up a couple of batteries (it never hurts to have a back-up, right?) in a little makeshift timing station.
Basically, we just taped our alligator clipped wires to either end of our batteries, and then shoved the batteries down over upside down plastic glasses, to tilt the alligator clips, and keep them in contact with the batteries (fancy, I know, but it worked).
We attached the other end of the wires to our motors, mounted in paper cups, and topped with doohickies from an old science kit (in this case a fan, and an axle) to allow us to easily see that the motors were running.
Then, we started a stopwatch, and waited.
Apparently the commercials with the drumming bunny aren't far off though, because our little fan and axle just kept going, and going, and...well, you know. Finally, about mid-afternoon, it dawned on me to pull one of the batteries from our Leapster (those are always dead), and charge that.
We took our solar panel, and taped up battery, outside. After testing that we had our solar panel positioned correctly, by seeing if it could run one of our hobby motors...
...we hooked it up to the battery, and left it to charge in the sun for a couple of hours.
We checked the battery in our electric charger (which has a nice indicator light) before, and after charging it in the sun. Before we charged it, it had showed one "bar of power" indicating a very low charge. After we removed it from the solar panel...
...well, it was exactly the same.
Leaving us, once again, with a number of questions to answers.
- Can you really charge a battery by just attaching it directly to a solar panel?
- Is our solar panel powerful enough for a AA battery?
- How can we tell when and if the solar panel is sending power to the battery?
- Do we need a diode to stop the power from draining back out of the battery during charging?
- Do we even know what a diode is, and do we have one rattling about somewhere in one of our old science kits?
They've completed their solar energy research, and are ready to apply, and share what they've learned in the real world, by traveling to Zimbabwe - where the sunshine is far more reliable than the local power grid. They hope to install a much needed solar array to provide back-up power for a computer lab, and library at the Theological College of Zimbabwe in Bulawayo.
As the students state in the video above, they have raised the funds for their travel expenses, and are now working toward fully funding the equipment end of the project.
Playing with mini-solar panels and scribble-bots is a lot of fun, but if you're looking for an Earth Day project to "make it real" this year, you might consider popping over to their RocketHub project page to learn more, and maybe even donate $10 dollars or so, to help the earth - and a few of the people living on it, at the same time.
Imagine being a college student in a country where the electricity goes off several times throughout the day, often for up to 2 or 3 hours.That's life for men and women enrolled at the Theological College of Zimbabwe (TCZ) in Bulawayo. But it doesn't have to be this way.
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