Turn Old, Dead Battery Into New Emergency Light and Even More




About: I am thankful for all of those who don't do anything at all. It’s because of them I do it myself. And I gonna do it my own way. The lazy way: think easy, do lazy.

Recycle is never getting old. It keep the world green and give old thing a new life. I love recycling, then I make new emergency light from a dead battery.

Step 1: Make the Battery Useable

My dad gave me this dead battery after he replace his motorbike battery. This battery is 100% dead. When I connect a 10 ohm resistor, voltage droped from 7.6V down to under 1V and current is 10mA.

Firstly I have to clear the negative terminnal because it rusted. I use WD-40 and RP7 but it just loose out a bit. Then with the help of a dremel, I can cut the bolt out.

Then I open the cover to fill water into the battery using a cylinder. The battery is dried so it absorb lots of water, and takes long time. After that I recharge the battery. It takes few hours to charge it up until it got 12,5V remain after disconnected. I test with a resistor and it shows the battery is worked.


  • Protect your eye.
  • Use gloves when working with battery.
  • Work carefully. Do not drop, short circuit, put into fire, ... the battery even if it dead.
  • Don't charge the battery indoor. It create lots of toxic gas.

Step 2: Stuff Needed

  1. An high power 10W LED (or two if the battery is strong enough)
  2. Soldering tin
  3. A switch
  4. Some wire
  5. Hot glue gun
  6. Cable stripper
  7. And soldering iron

LED focus len is optional.

Step 3: Soldering (super Easy)

  1. Trim the isolation of the wire, wrap the wire around battery's terminal and solder it. My battery negative terminal is a bit damged but no problem. After solder, check with a multimeter.
  2. Solder the LED and the switch. Look careful its terminal.
  3. Turn on to check
  4. Twist the wire and apply hot glue to the LED and wires to secure it.

The hot glue used to secure the LED chip, also absorb heat from the chip. The cool thing is this LED works with voltage between 9V to 12V so it still work even when the battery is running out.

Step 4: Ready to Use

The battery has a new life from now. Althought it not as good as new one but I can use it as an emergency light. I leave it on after a night but still full charge. The battery is totally fit-in-the-box and save some space. It doesn't have a fancy look but it make me feel good.

Step 5: Extended Version

I create a new part which show in the image. New part is parallel with the switch to work independently. It make this light is glow when it get dark. It's very good for garden light and fully automatic.



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    6 Discussions


    3 years ago

    Wow, I didn't know a dead battery could be turned into something so useful! Is it safe to fill the battery with water and charge it? I'll have to see if my husband can help my with this project, because it would be nice to keep some emergency lights in the house. http://a1fireprotectionllc.com/services/exitemergency-lighting/

    1 reply

    Reply 3 years ago

    Hi. It is totally safe to fill the battery with regular water because I having no trouble since the day I make it. Lead acid battery is extremely durable (which can be charged overvoltage) and totally safe to work with. It is always good to keep some emergency light around your house. I have 2 big emergency lights and 7 smaller lights. I never get enough of them ;)


    3 years ago

    I wish I knew more about working with LEDs. They take such little juice to light. I was an elctrician for 20 years but back when we only had high and regular low voltage lighting. I geuss I need to go back to school and learn something new.

    1 reply

    Reply 3 years ago

    LED is such a very good of lighting and also very easy to handle it in normal condition. You just need a bit of calculation ( there are many tool for this purpose like Electrodroid) or simply buy a LED controller. You have 20 years of experiences of electrical so I think it is really easy for you. I hope I can learn a lot from you (make an instructable plz :D )


    3 years ago on Introduction

    Nice, but since the battery was once dead it might be better as a convieience light. It might be dead again in an emergency.

    1 reply

    Reply 3 years ago on Introduction

    Actually I use it regularly than an emergency light but not as much as a convenience light. I did run it overnight, check before, during and after progress and it show the battery level is the same. I also check it regularly to make sure it always work well. Thank for your comment.