Introduction: Make an Emergency Phone Charger - MacGyver Style!

Picture of Make an Emergency Phone Charger - MacGyver Style!

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.

For more projects like this, check out

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

Picture of 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

Picture of 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

Picture of 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!

Picture of 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

Picture of 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

Picture of 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


illusive_311 (author)2013-02-26

I am contemplating using this for a "How to" project in college. I have tried three different cordless drills and am unable to get either one of them to turn by hand. Is there a particular type of cordless drill that is needed. Of the three that I attempted to use, it seemed as if something was going to "break" when I tried to forcefully rotate it to generate power.

omnibot (author)illusive_3112013-03-08

This will only work with Nimh or NiCad powered drills. LiPo or Li-Ion powered dittos have a protectioncircuit between motor and battery. Also some higher end models have PWM-circuits that does not allow for this kind of charging.
Though I'd mention it.

Good to know, thanks for mentioning it!

Can i use 14.4v driller instead of 18 v driller. . . plzz can you say sir

From my experience, if it feels like it will break if you force it, it usually does.

Check the settings on the drill. Is it locked? Is the torque setting set to the drill bit setting? Is the mechanism set to one direction or the other?

Also, are you pressing the trigger when you're turning it?

All these factors make a big difference.

Think of it this way .. operate it exactly as if you were drilling a piece of wood .. but do it by hand. Everything else is the same.

heavyweather (author)2015-09-30

I would hook up the drill to a bike.

Yonatan24 (author)2015-09-25

You mentioned that there are no capacitors, So is the drill's output DC?

Ibenos (author)2013-04-09

How much volt can i get from a toy motor?

Yonatan24 (author)Ibenos2015-09-25

It depends which kind of toy motor... there are billions of kinds of toy motors...

russ_hensel (author)2015-02-06

Just a note to let you know I have added this to the collection: Cordless Drills Hacking for Other Uses !


Take a look at a bunch of project involving odd uses of drills.

and for even more drill info


BronyC (author)2015-02-05

Hello. I was looking for ideas on a project on energy conversion. I was succesful on the results, but i couldn't find any explanations on how this works. i would appreciate it if you would kindly tell me how it works? the only conclusion that i came to had to do with polarity. But im not sure if i am correct.

nats1971.tan (author)2014-08-26

Hi king of random, i am trying to replicate your hand drill project but i am failing? Im using a 9v drill with a torque of 5? Do i need a higher drill to make it work? Thanks... In need of help asap...

triumphman (author)2014-03-07

In your "Microwave " scrounge video you show shorting out (grounding) the terminals of the dangerous and deadly component. These things contain very high voltages that have killed a service technician that got grounded. People should be made aware of this. Especially untrained young people. Thanks, for the great ideas. Recycling and dumpster diving are my passion!

nbwriter (author)2014-02-12

I loved this project: It's what practical engineering is all about.

From what I can tell the operator has to hand-crank for 3 hours at a constant speed to attain a fully charged phone. I'm reminded of an english inventor who developed a hand-cranked radio (for developing countries). I think he got it into production.

I know there's gearing systems around that will reduce the number of "cranks" needed. (Maybe resistance could be reduced if the gearing inside the cordless drill is removed or adjusted, too?)

Personally, I'd design a gear system and hook up the output terminals to a long-life battery. Then regulate the voltage from the battery to power phones and lights. This project really got me thinking.

Only one question: What was the make and model of the cordless drill used, please?

KeenaH (author)2013-05-02

Love your stuff man, ingenious

yankee2442 (author)2013-03-18

You need to enter this in the MacGyver contest!

I wish I could. I made it before the contest opened.

Timofte Andrei (author)2013-03-10

i have an idea and a question in the same time... is it possible to use the motor from electric drill as a wind generator without the gearbox, of course?... I have 4 expired number plates made from aluminum and i want to use them as some sort of blades for a small wind turbine, but i don't have any idea where to find a proper generator that could charge few UPS batteries. :D

I've thought about that, and I think it would work!

Chico da Rave (author)2013-02-17

I would sugest to add a voltage regulator, so you protect the cell phone.
It is very cheap and easy to use.

zwheel (author)Chico da Rave2013-03-08

   That was my first thought too. But... a voltage regulator is going to waste a lot of your power as heat. He did say it took 3 hours to charge the battery! If you are in an immediate emergency where you have to cobble something like this together just to call 911 I think you just want all the power to go to the phone. His method of manually regulating the voltage by varying his crank speed as he watches the battery indicator should be good enough in that kind of situation.

   Of course.. in an emergency is it really necessary to charge it all the way? Charge it enough to connect and make your 911 call already!

   If I was going to look for another source of cranking power, bike, wind, water, etc.. like he mentions I would definitely include a regulator! Anything like that though would already be a longer-term project, not an immediate emergency anyway.

   Also, if the phone actually implements the USB standard as written it should be pretty flexible with input voltage. The standard says USB ports should be 5V but devices should be able to handle more than that (I forget the exact number). Many cheap car power adapters actually get away with just sending the 12V from the car straight into the phone! (Don't do that) Not everything really implements the standard though so I wouldn't rely on that for day to day use.

You're right about that, but that's beyond the scope of this project.

Thanks :)

It costs just some cents, but ok.

I know you're right .. but this project was gear for someone who needs electricity with just things on hand. Most people probably won't know where to find a voltage regulator in a tight situation.

skipjack2001 (author)2013-02-19

This is actually pretty useful during a power outage.. or zombie apocalypse... or a shipwreck on a deserted island.

lol. I'm glad you found some value in it :)

The Lightning Stalker (author)2013-02-17

Good luck fixing your computer when you accidentally short those alligator clips together.

Nothing happens that I've been able to observe.

That is good because a lot of times it will blow a tiny fuse that is almost impossible to find; and that is a best-case scenario.

Thanks for the warning :)

dreams1 (author)2013-02-17

I've been wondering if there was some way to charge a phone using a bicycle... charge and get exercise, too.. :)

Definitely! You could use this method, and I'm also planning to to a project using an alternator to charge a car battery.

danny6114 (author)2013-02-17

Instead of a hand crank, couldn't you use a piece of steel or whatever of appropriate length to chuck into another variable speed drill attached to the charger drill and save some physical labor? As one might guess, I'm lazy.

If you have two drills and one is charged, you certainly can! You could also hook it up to a windmill or bicycle, etc for a lower labor approach :)

If you have a charged drill you could simply use its battery.

That's true. You'd have to introduce some resistors into the circuit, but it could work!

doctorkred (author)2013-02-17

My first commentary in Instructables is for you: Fantastic (sorry, but i write/speak english very bad)

In Blackberry is July 30, my birhtday :)

Hey that's great! I appreciate having your first comment! July 30th was the day I made it. Happy belated birthday :)

guicarlorobelli (author)2013-02-15

I've been hooked on your videos after seeing this one. I really appreciate your innovation and if I can ever find a place to buy acrylic locally, I will be building a water generator like yours. Thanks!!

Thanks for your awesome feedback! I decided to do the step-by-step instructables because the website seems to like them better. Thanks for checking it out again :) I have a lot of new projects I'm working on so am happy to get new stuff to you soon!

The step by step approach is what Instructables is about ... I am getting tired of the "show off" Instructables that actually don't instruct you about the project.

In short, Thank You Sir.

You're welcome! :)

I also prefer the step-by-step approach. It forces the author to focus on what the reader needs to know whereas many videos are bloated. One recent one in particular (not yours) contained 10 minutes of a guy cutting strips----no commentary with dimensions or other useful information, just cutting... Not only was this mind-numbing, but frustrating as he was using the table-saw incorrectly and very dangerously. If an inexperienced person follows his cutting technique and gets injured, who's liable?

In another case, I paid $50 for a 20-minute video of another guy hand-assembling an extremely simple electronic circuit. Such a video should have deliberately been aimed at "super-dummies" who've never assembled anything before. Otherwise, a proper schematic with the correct component-descriptions on a single A4 page would have sufficed. If further research reveals that I can legally re-publish, I will be putting it up here as an i'ble.

ericocean (author)2013-02-16

Some things in your projects always make me smile: this time it was the 3 hour cranking time to charge the phone battery. Valiant effort! It made me think that you could possibly walk in under 3 hours to where you intended to call in the first place. But that would not nearly be as instructive or as much MacGyver fun. Nice creative use of your grey matter, super project, good fun, great presentation as always. Thanks for that.

Thank you! In reality you'd only have to crank for about 10 minutes to get enough charge to make a phone call. I just wanted to see how long it would take to completely charge the phone.

Thanks for your feedback, and I'm glad to hear you appreciate the little details!

FlippityWidget (author)2013-02-17

Just curious; what's the chance of damaging the phone by "cranking out" too much voltage? Other than that I really like this idea. I suppose if you're stuck somewhere and your phone is dead and you have an emergency and you have no other way of charging the phone AND you just happen to have a rechargeable drill with the right equipment to pull this off it's worth the risk of damaging your phone. I'm more interested in how this could be applied to charging larger batteries such as lead-acid car batteries. Also, this makes me wonder what other devices I might have around the house that I could convert into electrical generators in a pinch.

Thanks for your feedback and your question. I believe this would actually work better for charging larger lead-acid type batteries. Higher voltage batteries would require spinning the drill faster so maybe it could be hooked up to a bicycle to accomplish that. I didn't notice any damage to my phone from doing this, but my goal was to just spin it barely fast enough to get the charging symbol. That was my safeguard against over voltage. I hope that helps!

Treknology (author)2013-02-17

Please note that if the selected drill has any form of "electronic speed control", it will require more dis-assembly than merely removing the battery as such electronics will probably impede the original intent of this project.

I also suggest connecting your USB wires directly to the battery contacts (or internal equivalent). The use of "foil" introduces more problems than it solves.

Was this just an experiment, or did you really need to charge your phone manually?

JamesRPatrick (author)2013-02-16

Now I have a use for my broken Black and Decker!

Perfect!! :)

About This Instructable




Bio: Random Weekend Projects
More by The King of Random:5 Ways to Start a Fire, Using Water How to make a Batarang like "The Dark Knight"How to Make Ninja Stress Balls
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