No More Wasting!... Let's Make a Simple Solar Charger




About: A DIY enthusiast.

Sometime, we aren't aware or taken for granted that everyday we waste our precious natural resources especially fossil fuel in form of routine used of electricity to power our things.

And I've... used a lot of it to charge my drone.

Now, in a 10 minutes' instructable, you can give a small contribution of saving Mother Earth for the future generation.

This is an instructable of making your own DIY solar battery charger from very simple components.

Step 1: What You'll Need

Step 2: The Diode Connection

Firstly, I connect the two end of the diode to the wire connectors.


Please make sure that the silver lining on the diode will be attached to the positive terminal of the battery. It will prevent the current from back flow to the solar panel thus, draining the battery that we want to charge.

Step 3: The Holder Connection

It's easy to connect to the battery holder because the wires are in red and black colored (red wire connects to the battery's positive terminal and the black wire connects to the battery's negative terminal).

The red wire is attached the diode directly to the silver lining's end and the black wire is attached to the empty connector slot.

Step 4: The Solar Connection

Next is the solar panel setup.

Matching the colors of the wires, I attach the other end of the diode (not with the silver lining's end) to the red wire of the solar panel. Then, I finish the process by connecting the panel's black wire to the connector slot that previously connected to the battery holder's black wire.

I hope you can complete this 'ible in 10 minutes or dare to break my record!

Step 5: The Charging

Lastly, a step to be a Hero saving Mother Earth.

I plug in a rechargeable battery to the battery holder and bring out the solar battery charger out in the sun to charge the battery.

This is a formula to calculate the amount of time to fully charged the battery.

The solar panel produce about 7.20A.

If you convert it to mA then, 7.20A X 1000 = 7200mA (amps X 1000).

The battery is 2500mAh, and how long it required to fully charged is 2500mAh/7200mA = 0.347 hour.

The conversion of 0.347 hour to minutes is 0.347 X 60 minutes = 20.8 minutes!.

Then, it will be about 21 minutes in the sun for the battery to fully charged.

For an hour, you can charge simultaneously three 2500mAh batteries in a parallel circuit.

(If my calculation is incorrect, please leave a kind comment below).


If you want to charge multiple batteries in a session, you can create a parallel circuit.

(Please refer to the circuit diagrams).

Points of Caution

Since the current is 7200mA and it's too much for a single 2500mAh battery, I suggest that the setup of circuit is a parallel circuit of at least three batteries. However, anything relating in charging a rechargeable battery of any kind must be handle with extreme caution.

This setup will lessen the current load on each battery to be charged and added a load to the circuit, thus less heat generated or else the battery will damaged because of over current.

I tested one of the battery and it register about 6.9 ohm before the charging.

And, please do it outside.


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If you have anything to improve this documentation, to suggest an idea of refinement, or to query then please leave a comment below,

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Thanks for giving an apt appraisal for my 'ible.



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    8 Discussions


    2 years ago


    Most of batteries are not support 7.200mAh charging current. It may (highly chance) cause explosion or fire your house etc.

    Also there is not any over-charge protection. This could be very dangerous with any lithium based batteries (even, might be with NiMH). Need to mention used battery type. Else, someone may fire its house or explosion can be occured.

    If you are exactly do not know what you are doing, "Beware about this instructable!".



    7 replies

    Reply 2 years ago

    Please, do not understand me in any wrong way. Firstly this project can
    still can be quite handy (if you are out all day and want to recharge
    the batteries as you go). Secondly I think it is awesome if many people
    play around with electronics in general and solar panels in particular -
    and I love the fact that you did! But my believe is, that instrucables
    is to educate people, so I think it is important to tell the whole

    So here it is: I would go as far as to say: "If you don't know what you are doing, don't do it.. If you know what you are doing, I don't have to tell you not to do it."
    There is a good reason proper wall chargers cost >40$! They do measure a lot of parameters, analyse them and decide on that data what to do (especially when charging several batteries in parallel!). The charger presented in this 'ible will reduce your batteries lives considerably (over/undercharge, too fast charge), give you less power (since you have no indication on how "full" the battery is (a solar panels output depends on many factors, such as temperature, sunshine, angle to the sun etc + if you put 1000mAh into a battery, you will only have ~800mAh "in it") you will need to stop charging at a lower level than full or risk overcharging = more or less destroying the battery) and risk your health (overcharging = battery may explode).
    If you want to improve this 'ible I would really recommend using a professional charge controller that is usable in cars (you can then basically hook it up to a small 12V lead battery and add a 12V solar panel).
    Second thing is, that this is NOT environmentally friendly (sorry to say that). Just because something is solar does not mean, that is is "green". Solar panels take a lot of energy to produce - this is called "gray energy". If you hook up the solar panel on your roof and it gets an average ~5hrs of sun each day, you might be at +-0 CO2 (energy used to create the system - energy the system produced) AFTER 5 YEARS! Unless you charge batteries professionally, this solar panel will never see this kind of usage. So the amount of energy put into the production of this system will be higher than the energy saved/produced by it.
    Again: Please do not let this stop you from working on electronics in future!


    Reply 2 years ago

    Nice details on points. I was in a hury when i was commented, so wasnt give details on it. Thank you for details.

    Also my warning comment was about batteries, not solar panels. As I said before, Lithium based batteries a lil bit dangerous when you are charging or discharging them. Need to read more about them. "" is a good source about batteries to start at.

    Electronic is fun to play in "safe border"!

    "this is called 'gray energy'" Im not with you on that. There is no "green energy" which is %100 efficent nor transfering big amount of energy with less effort (Also not trying start a polemic. Just saying).




    Reply 2 years ago

    Sorry, I don't get your point about the gray energy. My personal definition of green energy is, that you have a technology that produces (or to be more physical: converts) more usable energy (heat, electricity, ...) than was put into it from classical sources (gas, coal, oil). So if it takes 10MWh to create a system (e.g. a solar cell) that will only produce 1MWh until it breaks, I would not call it green. If you have a system that only requires 1MWh and can produce 10MWh I'd call it green.


    Reply 2 years ago

    Saying same thing. There is no green energy for real. Taging it as "green energy" is a PR tactic.


    Reply 2 years ago

    Thanks for sharing your knowledge with us...


    Reply 2 years ago

    Yes... must learn more about electronics :-)

    Thanks for commenting.


    Reply 2 years ago

    Thanks for commenting.

    I'll make some adjustment to the 'ible so that it will NOT exploded or burn someone's home.