Jump Starting Car With Drill's Battery

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Introduction: Jump Starting Car With Drill's Battery

About: Innovative Projects, Diy's, Life Hacks

3 years ago, I published an Instructables where I demonstrated a way to jump start a car using a battery from a drill.

Some people were not sure if it will work on bigger cars as the car I used at the time was Kia Picanto.

In this improved Instructable, we'll jump start 2009 Opel Zafira, 2L Diesel and discuss the best practices.

Step 1:

You'll need a fully charged battery from a drill or other power tool.

It's important that the battery is indeed fully charged. A half charged battery might not give you enough power.

I used 14.4v battery.

Batteries between 12v - 18v should work just fine. Some people even reported using 20v batteries with great success, but I wold not go that high.

Depending on the battery you use, you'll need to get creative.

I connected small alligator clips to extend battery terminals. I put a sponge between the clips to avoid accidental s/c.

Step 2:

First you'll want to connect the positive (+) clip to the dead battery, then the other end to the drill's battery.

Step 3:

Then I connected the negative (-) clip to the drill's battery and the other end of the cable to unpainted metal part of the car. In my case it was a bolt.

Wait between 5 - 10 minutes before trying to start the car.

If you're lucky, you'll be able to drive away.

Some thoughts:

I did a few experiments and found out that the battery could only start the car once. If I stopped the engine and tried to jump start the car again, It was not possible - you would need to charge drill's battery again.

That's why it's a good idea to let battery charge for a few minutes before trying to start the car.

Is it safe?

Nothing is 100% safe.

I would only use this method to start the car if there is no other way to do it.

It's unlikely that you'll damage your car or the car's battery by doing this.

Cars are made to be abused. They have a voltage regulator that prevents overcharging and protects electrical system from the damage.

If something would fail, most likely it would be drill's battery....but it's unlikely...unless you use it for jump starting cars all the time.

Use this information at your own risk. As I said before, this method of starting a car should not be a danger to your car or to yourself, but different batteries act differently. There is always an element of danger present.

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    8 Comments

    0
    PaulG78
    PaulG78

    5 months ago

    I am wondering if this is brilliant or stupid. Thought I would work out some ruff calculations. Very ruff, I'm not an expert in drill batteries. Let's say a dead car battery is 11v and your leads are good 5 ohms from cell to cell (20v -11v)/5= 1.8 amp well within the spec. A 5 cell battery can probably put out 25 amps lets say they are fused at 20A for safety. Will a 0v car battery pass that current (20v -0v)5ohms=4A. Still very safe.
    What if we used out standing leads, how little resistance would be under 20A on a dead car battery. (20v-0v)/1ohm=20A. It is hard to get under an ohm leads when not in a lab, it is hard to get a car battery to 0v.
    Offhand this looks like a brilliant idea. I would do this to my car.

    0
    SolutionEngineer
    SolutionEngineer

    2 years ago

    20v batteries are 18v nominal; it is for marketing that some manufacturers tout the fully charged voltage for the model lines. Whether 18v or 20v, they all use 5 18650 li-ions in series circuit. The extended batteries use parallel attached multiples of the original number of cells, varying by voltage, but usually in multiples of 3.7v li-ion chemistry; 4.1v is the fully charged voltage of a li-ion cell, but under load, 3.7v is what is sustained. It is specifically for marketing, Milwaukee, Makita, and Bosch(until recently) stuck with 18v nomenclature for their tools that are more powerful than most tool lines labeled 20v, though the actual voltages are identical.

    0
    Chris W.J
    Chris W.J

    3 years ago

    This is a great idea, also for a dead motorcycle battery.

    0
    elpayo
    elpayo

    3 years ago

    Thank's. it's a good idea in case of trouble

    0
    aideym
    aideym

    3 years ago

    I'll remember this next time my MG won't start. Which probably won't be long.

    0
    Left-field Designs
    Left-field Designs

    3 years ago

    It's a little unclear, after 15 mins are you disconnecting the drill battery and then starting the car? If so this isn't a jump start, it's more of a boost charge. If the battery is still connected you are at very real risk of damaging the drill battery as it is not a deep cycle battery like the one in the car and the in rush of power from the alternator after the engine start could cause the battery to explode or at least burst and leak (either way destroying the battery). I don't mean to be negative, just looking for clarification and if my car was stuck and this was the only way to get going I'd certainly try.

    0
    ShakeTheFuture
    ShakeTheFuture

    Reply 3 years ago

    I waited 10 minutes before starting the car. The battery remained connected.

    Cheers!