Introduction: Make an Emergency Phone Charger - MacGyver Style!

About: Random Weekend Projects
In this video, you'll learn how to "MacGyver" a 40 Watt Electrical Generator from a cordless drill and a few household items.  Here's how to charge a phone, illuminate small lights, and make electricity in a pinch.

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Step 1: Watch the Video!

Note: 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, and are comfortable with, the risks.  Back up your data in case your phone is adversely affected and your data or equipment is damaged as a result.

Step 2: Household Items

There's no charge for this electricity! All you'll need for this project 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: One More Thing You'll Need

You'll need a way to connect the power you generate to your phone.

Look for an old phone charger you might have, and cut it in half.  We just need the piece that plugs into the phone.  You could even use a USB charger cable like the one I found.  

Inside the cable you should see 4 wires.  White, Green, Red and Black.  The Red and Black ones are the only ones we'll need for this project.

Note: For this project I used an old Blackberry Pearl.  If you are using a smart phone, the white and green wires may need to be shorted out or connected to a "dummy load" to get a successful result.  (I haven't tested this method yet but have had feedback from other viewers suggesting this is the case)

Step 4: Making a Hand-Crank 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 5: We've Got 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. 

Ideally, this could be hooked up to a bike, water power, or even a windmill to generate effortless energy.  And if done carefully, the energy could be stored in a battery for later use!

Step 6: 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 in a previous project!

Step 7: Other Projects

Well, there's a bare-bones 40 watt electrical generator that you can make in a pinch that will charge batteries, illuminate lights, and provide a little electricity in a pinch.

If you missed the video, you can still see it here!

If you liked this project, perhaps you'll like some of my others. Check them out at