Repurposing used Li-ion cells

In the previous blog, I've shown you how I harvested lithium-ion cells from a used Macbook battery.  Today, I will show you how we could put these into use.  You must test each cell and the "good" ones must show at least 2.7 volts.  You discard cells that are below this voltage point as it could be potentially dangerous to charge them up.  My experience however, I can revive some of the bad ones by charging very low current using a professional variable current, li-poly charger.  Never try 0 or negative voltage cells.  Ever.

I have stacked the cells up and connected them all in parallel.  So positive to positive & negative to negative.  It gave me 3.7 volts from a discharged state.  Good!

Opening up one of my portable usb chargers (power bank as is fondly called in my place), I soldered the battery to the corresponding polarity input in the circuit.

My low capacity power bank is now monstrous!  If only I can find a suitable case for it now that it's grown.

Harvesting Lithium-Ion Cells from used laptop battery

Very hazardous!  Kids don't do this without your parent's supervision!

I admit it! I am a certified "battery junkie".  I own dozens of rechargeable AA/AAA batteries from NiCads/Ni-MH to non-rechargeable Alkaline ones that I force to charge.  I recondition and maintain at least 5 used car batteries I refuse to let go.  Not to mention 4 used 12-volt sealed lead acid and 2 6-volt Hawker from the office.  A dozen USB power banks with or without its own battery, some lithium ions here and there, a couple of  laptop/polaroid batteries... I even created a rechargeable lead-lead oxide cell from pipes myself which won a "science fair project" for my relative.  And still it doesn't stop me from doing this.  I guess I can never have enough stored energy.  Especially for power-hungy tablets.

This is my donor:
A Macbook White used battery

       Remove Torx screws then remove the aluminum cover.

                   Controller circuit.  We won't be using it.

Cut off connections from the cells.  Be careful not to create a short or it may spark and explode!  Then very gently, using an old credit card, pry the cells off the enclosure.

Here are the harvested Li-ion cells.  These can be used for another project.