How to rejuvenate a nimh cell

Written by kristin jirovsky
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In a laptop, the first thing normally to wear out is the battery. These can be expensive to replace--anywhere from £32 to well over £65. Because of the high cost of replacing a laptop battery, also known as a NiMH cell, you should take steps to rejuvenate it. Rejuvenating a NiMH is different than rejuvenating a NiCd battery, so do not use these steps to try to rejuvenate a NiCd cell. The main differences between NiMH and NiCd cells is that NiMH cells are lighter and NiCd cells contain the heavy metal cadmium. NiMH batteries are also touted as being the easiest to rejuvenate. Do this with care, because it can destroy the battery if done incorrectly.

Skill level:
Moderately Challenging

Things you need

  • 12V light bulb
  • Paper clips

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  1. 1

    Drain the battery life. Keep your laptop running until the battery is completely drained and shuts off the laptop. This should be done when no items are open or left unsaved, since you may lose important information when the battery dies. Turn off power-saving features to speed things up. This can be done by clicking the battery icon, located at the top right corner of the screen on a Mac or the bottom right corner on a PC. Select "Energy Saver Preferences" and change settings to "Never" to ensure that the computer will not go into Sleep Mode while you drain the battery.

  2. 2

    To drain the battery further, attempt to turn the computer back on until you get no response at all. Then, remove the battery and locate the connector area where the battery connects to the computer. Place a paper clip on the + and - sides of the connector area of the battery. These are most often on the opposite edges of the connector area. One paper clip should go on each side. Connect two wires, one to each paper clip. Take the 12V light bulb and connect the two wires to the light bulb. The light bulb will light up when the wires are connected properly. Watch the light bulb, and when it begins to dim, stop the process by removing the wires. Remove the paper clips from the + and - sides.

  3. 3

    Replace the battery. Make sure it is put back into the laptop correctly. Now, plug the laptop into a charging source. Leave the computer in off mode until the battery has completely recharged. With success, the battery will now run at a steadier rate, not declining in battery life as quickly.

Tips and warnings

  • There are no guarantees this will work. You might end up destroying your NiMH cell. It could even explode. Proceed at your own risk.
  • Do not allow the light bulb to go out completely, because it could damage the battery.

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