Reuse Old Laptop Batteries for Prolonged Use of Car Toys (or Any Other Device)

My kids got a new toy for birthday They were very disappointed with the performance of original battery 700mA which i suspect that is much lower. I decided to cheer them up by fixing their toy

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Step 1: Creating the Charger

I used old HTC charger 1Amp and old USB keyboard. I connected with the improvised connector with Black and Red wire. Since batteries are 4V i use 5 Volt standard charging (for mobile). Its very important to use 1Amp charger not less (since many cheap products mislead costumers).

Step 2: Parts

My fathers laptop battery died. I purchased new one but decided to see what in the old battery. When opened i saw an electronic chips (which probably regulates voltage input and output) with 6 batteries. Batteries where arranged in series of 3 series of 2 parallell batteries. In short every battery has 4 volts x 3 series to make an output of 12v ( or 11.8 ).

In picture you see 2 of 3 batteries pack extracted from the llaptop battery . Other battery is original one (700mA) .

Step 3: Result

Last and not least.. Laptop battery electronic chip protects battery from overcharging. Be carefull not to charge beyond their voltage. In my case, after disconnecting from charger i check the voltage of batteries with multimeter. If it is around 4.0V its OK.

I tested the car myself for an hour...The results are impresive. Even my kids don't have nerves to discharge the battery.

Lessons learned:

Never throw away llaptop batteries. They are very high quality and can be useful for anything

Step 4: Videos

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    8 Discussions


    4 years ago

    ​LOL, that's fast! Thank you for sharing the video.
    You can embled videos from Youtube. Copy the embled code and paste on your instructable.
    This are the charger I use for individual cells, or cells in parallel


    4 years ago on Introduction

    Newtonn2, thank you for your informations. I successfully embedded codes from youtube


    4 years ago on Introduction

    Newtonn2, thank you for your advice. I agree that it should be very careful how you charge. 6 cells battery are usually in series of 3 of 2 parallel (as i stated in the instructable. You are right i forgot this to add. 4400mA battery is rated from the manufacturer. it turns out that these single batteries are 2200mA (when not connected paralelly. I strongly advice that when charging to stay on site since overcharging with higher Amperage or beyond Voltage capacity of the battery can lead to fire. Kids should not charge it, or it has to be charged with intelligent charger . I want to share my experience. I played with that toy for hours, the battery voltage dropped from 3.99V to 3.74V. I charged for less than 10 min, and i measured the voltage 4.10. So BE ON SITE or get an intelligent charger. I don't have video right now, but i adapted second set of batteries (just a test, without soldiering) on second toy. Look up this tank. Can you tell me where to buy INTELIGENT CHARGERS which stop charging at certain Voltage???


    4 years ago

    Hi there. Thank you for sharing your instructable. I like to recycle components and batteries as you do. Just a warning I thought you may appreciate: be very careful with this Lithium batteries, they can explode and cause fires by not only overcharging them, but also if you charge then at a rate higher than 1/3 of the rated mA. There are small charging circuits on ebay for about £1, but they will only charge one cell, or a few cells in parallel.
    Do you have a video of that baby going? I'm sure it is petty fast with the new cells!


    4 years ago on Introduction

    thank you for sharing this incredibly clever and 'green' 'ible! well done, and thanks for sharing your lessons learned!