Jump-Start Your Car With Drill's Battery




About: Innovative Projects, Diy's, Life Hacks

My car's battery was dues to be changed. Every time I started the car, I could hear that one day it will not start.

Monday morning, I have an important meeting at 9:00. I am ready to leave my house, but I can't start the car.

Battery does not have enough juice. In the area I live, there are no cars around. I could ring my friend to give me a lift or a jump-start, but it will take at least 40 minutes.

There is no way I can push-start my car.

Time is running out. I go inside and pull out the battery from my drill.

It's 12v battery, just like my car's.

I tape 2 screws to the batteries + - terminals.

I connect the both batteries together using jump leads.

I wait 10 minutes before trying to start my car. After 10 minutes, I manage to start my car.

Let's go to the meeting and on the way back, pick up a new battery.

I got lucky this time.

A made up story, but it could be real :)


This little trick should work the best if:

  • Your drills battery is charged, big capacity and the same voltage as car's battery or a little bit higher.

I used 12v drill battery to hook it with my 12v car's battery. I believe it should be fine to connect 14v, 16v battery, but I am not 100% sure at what point do you cross the line, putting your car's electronics at danger. That's why I recommend using the same voltage battery. If you know the answer, please let me know in comments.

  • Your car's battery is not completely dead.
  • If you own a small car with a small battery.

It's not the smartest thing to do, so only try it out if there is no other way. There is always a small chance of destroying your drills battery or messing up your cars electronics. 99% of times nothing bad will happen, but let's put it that way. I would not jump-start my "Porche" this way.


Step 1:

  • Pull out the battery from your drill.
  • Tape 2 screws to battery terminals.
  • Connect both batteries together using a jump lead.

Positive to positive, Negative to Negative.

  • Let batteries to sit for around 10 minutes or more.

  • After 10 minutes, try to start your car.

You have 2 options.

To disconnect the battery and try to start the car or leave the battery connected and start the car.

Leaving drills battery connected should give better results, but could damage it.

I only waited 8 minutes before trying to start my car. I expected for the engine to struggle, but it did not.

Car started - Ouu Yeah!

Here is another reason to keep your drill's battery charged!



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    80 Discussions


    2 years ago

    I once bought an old BMW 7 series from my neighbor- computer in the trunk, one of the first on board GPS, etc. One of the accessories was a little battery charger that plugged into the cigarette lighter, with a long cord and little terminal connectors. I never used it but always wondered...


    4 years ago on Introduction

    Or you could have taken off your alternator belt and use the drill + socket to spin the alternator.

    7 replies

    Reply 4 years ago on Introduction

    I don't think my drill could spin it. Maybe with something more powerful. That's a good idea though.


    Reply 4 years ago on Introduction

    Without the belt on, you can spin it with your hand. Maybe I'll add an instructable for this. The problem is clearance, I don't know if there is room on modern cars.


    Reply 4 years ago on Introduction

    Three points against your plan... First, an alternator needs a minimum of 2000 RPM to start to give enough voltage and current to charge a battery. That's over the max RPM a cordless drill will spin (some might do 2000 RPM, max). Second, it's very inefficient. You would be taking a electricity from a battery and converting it to mechanical energy of the spinning drill; you'd then transfer mechanical energy to the alternator which would take this mechanical energy and convert it back to electricity to charge a battery. You would be better off off using the drill batteries to charge the car battery as this article suggests. Third, the alternator may spin freely while off the serpentine belt and with no electrical load, but as soon as you attach a heavy load (like charging the battery) the alternator is going to resist and and I'd be surprised if a cordless drill had enough torque to keep the alternator spinning, If it could still spin it would certainly be much lower than 2ooo RPM. More likely the overload detector will shut off the drill (most Lithium Ion drills these days have overload detectors to protect the batteries).


    Reply 2 years ago

    My husband swears he can jump a car off with a drill batterie i not found where anyone says it can be done but soon will find out any min but im a girk and i know nothing about cars i thought blinkers needed fluide and i put oil down my dip stick one time so he can pull one over on me and i never know


    Reply 4 years ago

    Not nearly enough RPM that way.


    Reply 3 years ago

    Sure there are. if you use an impact driver there is enough RPM


    3 years ago

    Read a number of comments,and they were interesting. some good and some not so good. As being a mechanic and truck and construction equipment operator most of my life, I can relate to the problem of starting older and newer equipment. older equipment is easier to start, just get it to roll over and have some spark and it will run. newer is more finicky, the computers/electronic ignitions shut down at about 10volts. the starter can draw the voltage from them with a low battery it may turn over but have no spark.the newer trucks have similar problems they are now computer controlled, no more put it on manual and tow a dead truck to start All highway trucks in the united states, other than military trucks are 12 Volt, some use 24 Volt to start but most use 12 Volt to start. most construction equipment used 24 volts.

    Just my overations over 70 years


    4 years ago

    cool trick!

    And it cannot be stressed enough:
    NEGATIVE TO NEGATIVE (black, often car-body)

    if you do it like + to - it will create massive sparks, local plasma, redhot metals, options for loosing fingers (burn thru) and most probably a dead car.

    8 replies

    Reply 4 years ago on Introduction

    It can also cause the vehicle batteries to overheat and explosively vent the acid. Personal experience, no fun not knowing how well (or if) your eyes will work for several weeks.


    Reply 3 years ago

    About ten years ago I was a Safety Instructor at a Nat'l Auto Auction company. At that time statistics showed the the number one cause of blindness in North America was jump starting a car improperly. Safety glasses are inexpensive. Store them with your cables. We had one car battery explode inside a garage and shot a section of the battery through the metal roof. Be careful.


    Reply 4 years ago on Introduction

    You made it sound so great and then ruined it with the whole losing fingers/dead car part... ;-)