DIY Hand Crank Phone Charger

Introduction: DIY Hand Crank Phone Charger

In this Instructable you’ll learn how to make a small hand-crank generator that can charge your phone or illuminate a small lightbulb.

Step 1: Disclaimer

This project is intended to be a "bare-bones" approach to generating electricity in a tight situation. There are no voltage regulators, no diodes and no capacitors to smooth the current. There may a risk of overheating and damaging equipment when operating electrical devices without a proper circuit recommended by the manufacturer.

It worked fine for me, but if you try this on your phone make sure you understand the risks. Back up your data in case your phone is affected and your data or equipment is damaged as a result. I take no responsibility for anything that happens. Not that I think something will.

Step 2: Items Needed

Most of the things you’ll need for this project you probably have around the house! All you'll need is...

1. A cordless drill
2. Anything you can find to help secure it in place and spin it by hand.

I used;

* A piece of wood 2"x4"
* Some yarn
* 1 mixing beater
* 1 salad fork
* A piece of aluminum foil
* Some Scotch tape

Step 3: Making the Generator

Step 1: Remove the battery from the cordless drill and look up inside. You should see 2 terminals where the battery provides power to the drill.

Step 2: Use the aluminum foil to fashion make-shift wires that connect to the terminals. (Salvaged copper wire is even better if you can find some).

Step 3: Secure your drill to a surface like a piece of 2"x4" with the trigger pressed "on". I used plenty of yarn to hold it down tight.

Note: The trigger needs to be on, and the torque setting at it's highest.

Step 4: Insert the mixing beater into the drill chuck and make sure it's tightened so the beater won't come out.

Step 5: Add the salad fork through the mixing beater to act as a crank handle, and hook up your charger cable. Hook the red wire to the positive lead, and the black wire to the negative lead.

Note: Polarity DOES matter! If your battery isn't charging, you've probably got the polarity reversed. You can either switch the cables, or set your drill to reverse and crank the opposite direction. This will reverse the polarity you generate and should fix the problem.

Step 4: Power!

Now all you have to do is twist the rotating end of the drill, and you'll be generating electricity at the contact points where the battery would normally connect.

The little plug symbol on this phone appears at around 5 volts, and shows that it's charging. I decided to crank just fast enough to keep the charging symbol displayed, to reduce the risk of over voltage. On my drill, a cranking speed of 100 RPM yielded about 5 volts DC.

I used some clamps to secure the device to a desk for better leverage. Shorting out the leads on my multimeter returned a value of 5-6 volts at 7-8 amps. That's a 40 watt human powered hand crank generator!

The faster and harder you can crank the drill, the higher the voltage, and more amperage you can extract.

If you want to you could try to rig it to a bicycle or other device with a spinning component to get more energy with less effort. And if done carefully, the energy could be stored in a battery for later use!

Step 5: Results

It took about 3 hours of cranking, but I got my phone fully charged. The phone only accepts a very small current (about 94mA in my case), so it's not hard at all to crank. But if the generator leads are shorted out, or hooked up to a re-chargable battery, the effort to crank increases quite a bit! This is because you're pushing more current.

In retrospect, I think it would have been more efficient to spend 15 minutes cranking a larger current into a large 6 volt battery, and then charging the phone from that. But hey, you do what you can with what you have.

The charger illuminated an incandescent flashlight bulb, a super bright white LED, and there was even enough power to convert water into fuel with the OxyHydrogen generator made by the King of Random. (I suggest you look him up, he has some very interesting projects)



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    10 Discussions

    So awesome. And so much potential. People could generate so much electricity with the right gearing and battery set up. I've got a treadmill motor I'll give you for the cost of shipping if that interests you.

    8 replies

    I wouldn't worry too much about the diodes, regulators, etc when using the hand crank. Just because the battery isn't in too much danger of overheating unless you charge it up to 100% or at a voltage that's way way higher than what it is supposed to take. If it's dying, it's thirsty, and if it gets too thirsty, it's dead for good.

    It would 15 dollars or less cross country. If I remember correctly its around 120v dc. It also has a threaded shaft. Im thinking with the right gearing you could get some serius power out of it. Could be as simple as find a large wheel and using it to turn the small diameter motor shaft by friction. Like friction drive bikes. may be a good way to get more power out of your drill to. Peat the egg beater shaft up against the rear tire of a bicyle and get to pedalling. I can try to set up a 'best offer' ebay listing if you're interested and your 'best offer will just be whatever shipping is, plus the 10% that ebay takes, so instead of 15 it would be around $16.50.

    Electric hospital bed, you know where the feet and head go up and down.

    I also have a hospital bed with a crazy gear reducer built in, wondering if that could be cranked backwards to work as a generator somehows.

    I'll check for you. I'm going to the post office today anyway.

    That's a pretty funny idea :) It's good to have a backup if you lose your charger I guess!