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.