Simplest Way to Recycle Old Laptop Cells

Get your Hands on to some Old Laptop Battery Pack or any old Rechargeable lithium ion cells .

got these batteries from my 8 year old laptop .

Break the Plastic Casing , Carefully ,

without damaging any cells ( if you use extra force , they could puncture up , leak and catch fire ! )

once you have the cells out of the plastic casing

Cut them away from BMS board and separate them individually .

Clean the terminals properly , so the spot welds are smoothed and not bumpy .

Step 1: Identify the Cells From Labeling

Identify the cells , from the printed labeling on the shrink wrap covering .

in my case they were trusty old Li-ion ICR18650 22H

look up the respective Data Sheets on google .

Get to know the original Manufactured Capacity of those cells.

Study the charging/discharging curves and Capacity cycles .

Also Test the Voltages on them .

label each cell with numbers , and make a table in your notebook .

keep tabs of original voltage at which you found the cell , and take readings for each time you cycle them in charging or discharging .

after charging the cells , keep them away in cold dark place for few days ,

check the voltages on cells in storage after few days , if the voltages dropped significantly , throw the cell away as it is bad and will damage your project .

Step 2: Charging the Cells Using TP-4056 Board .

Tp- 4056 is a great board to charge your batteries of less than 4.2v

look at the spec sheet .

this board is simple to use . plug and play applications .

can be used with a micro USB charger . is capable of charging at maximum of 1 amps

it comes with battery protection for overcharge and over discharge ,

Read the chart which shows how to sort your recycled Li-ion cells on capacity and voltage state.

Step 3: Simplest Way to Discharge & Estimate the Capacity of Cells .

You don't need to Spend a lot of time and money on building a Discharge circuit .

no need of n channel MOSFET and LCD displays .

you just need an Arduino board , a good 5 watt Resistor ( 1 ohm to 22 ohm works fine )

I had both 1 ohm and 22 ohm 5 watt resistors , so tested both.

basic knowledge of P=IV and V=IR

Cell is connected with the resistor and Arduino's Analog pins Read the Voltage drop across the resistor with respect to Time , providing with a rough estimate of the capacity of your cells .

arduino sends output on the serial ports available for viewing on the computer , so you don't need any lcd or logger circuit , the IDE serves as a serial output port , you can print , record and chart your readings and get the capacity value.

If you are building small projects , you can use this circuit to check if your batteries hold any charge .

if you are building a power wall level project , i recommend investing in a proper Capacity tester .

I am using my cells for LED lights as a load for overnight functions and charging in daylight using Solar power , so these batteries were good for this project and over 1.3amp each , after 8 years of usage , i was surprised they could retain even 1 amp and hold the voltages for long time in storage .