How to Make an E-bike Battery Using "dead" Laptop Batteries.

In this video I will explain how to recycle "dead" or not workin laptop batteries to give them a "second life". With the batteries I recovered I've built a 36v 24Ah battery for my electric bicycle.
Please bear in mind that the "18650" cells used in the video are Li-Co chemistry. This means:

- High energy density 
- Cannot be charged AND discharged  at more than 1C, going over this limit will cause lot of heat to develop and consequent risk of fire/explosions
- never discharge them to less than 3.0volts
- never charge them over 4.2v (stay safe at 4.1)
- Always work in a safe environment
- Use protective equipment if necessary
- Use common sense 

Of course you can use this batteries for other applications, I am just showing you what I used them for.

This work took me a lot of time but I learned a lot and gave me great pleasure when completed.

I hope you enjoy.

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    5 Discussions


    5 years ago on Introduction

    i might have to do this! my current bike has a 24v 36 AH lead acid pack weighing almost 60 pounds! O.o but its a "junk made bike, everything was free surplus. the motor is from a wheelchair and the only costly thing was a motor controller, 30 bucks.

    2 replies

    Reply 5 years ago on Introduction

    Hi Iden!You will notice the difference in weight going from lead acid to's a big change.You seem to be good with DIY,I am sure you will have no problems building the new battery!


    Reply 5 years ago on Introduction

    thanks! I have never used lithium ion cells, nor charged them, so i am charging my first one right now. i have an amp, volt, and temperature meter on it, and its probably not a good cell, it can hold a charge and it can run something, but it discharged rather quickly when only throwing out 2 amps. i got about 12x 10.8v 8.8AH laptop batteries from school today, and i am hopefully going to use them. if not, i have about 70 nimh cells from a drill battery i could use instead. on the picture i have, the black meter is voltage, the yellow is amperage, and the small silver is a broken meat thermometer :)


    6 years ago on Introduction

    Awesome video! I have been wanting to do the same thing too with the tons of old lipo laptop batteries I have accumulated. What kind of battery monitor are you using?

    1 reply

    Reply 6 years ago on Introduction

    Thanks Hellwarrior! I have been using some cheap "battery alarm" I found on ebay: I am making a video with a better alternative that has logging capabilities (not cheap though): Definitely if you have the $$ the second one is better, you can save very nice data and see the actual discharging curve, so it's very easy to spot dead or non recoverable cells.

    I have to say that a lot of laptop batteries are still good because the internal eeprom  is programmed to disable the charging after a number of cycles.

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