3.5V Solar Panel AA Battery Charger




Introduction: 3.5V Solar Panel AA Battery Charger

Hi everyone,
I'm Manuel and this is my first instructable so if you have any questions, don't hesitate to post a comment.
Today I'm going to show how to make a simple aa battery charger using the light of the sun.

Step 1: Materials:

For this project you need:

- A solar garden light (mine was bought in a dollar store)
- A diode with low voltage drop (I suggest 1n914)
- AA battery holder
- Soldering iron
- An obviously rechargeable batteries

Step 2: Solar Panel

Now remove the solar unit from the steak and open the unit by unscrewing the three screws at the bottom.
Inside there is a small circuit (with a transistor,a resistor and a led) and an AAA ni-mh battery.
The panel is at the top and it's easy to remove.

Step 3: Connections

At this point, using a soldering iron, solder the two wires of the panel to the positive and negative wires of the battery case.
WARNING: respect the polarity of the 2 wires otherwise battery will heat up and they can explode.

Step 4: Conclusion:

It takes a lot to charge up the batteries but it's an interesting project about "green energy".
I hope you enjoy this instructable and soon I'll post another project regarding solar energy... so stay connected!

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    4 months ago

    Sorry, but this seems wrong - don't you need some sort of load balancing? What happens when the batteries are fully charged but the solar panel generates more current - there is no overcharge protection so the batteries might burst and cause a fire. Or am I totally wrong here?
    Also how does this cuircut deal with the different levels of voltage generated by the cells? Sometimes you might get almost 5v while other times about 2v


    1 year ago

    Where does the diode come in? The only mention is that you need one.

    Solar panels
    Solar panels

    3 years ago

    Good INFORMATION. Really helpful
    For more solar panel related information Once VISIT THIS
    solar panel


    4 years ago

    This is what I have been looking for. I plan to get a weather station soon that takes a few AA batteries. I'd like to run the wires from a solar cell(s) to trickle charge the device so that I can either extend the run time, perhaps indefinitely. Is there anything different I'd have to do?

    DIY Hacks and How Tos

    You can also wire multiple solar cells together to speed up the rate of charging.

    ManuLab DIY
    ManuLab DIY

    Reply 4 years ago

    Yes, of course. This is a basic set up and so it can be improved in several ways.
    Thanks for your observation!