Rechargeable Lithium Battery Link
Since most rechargeable lithium batteries are 3.7 volts or multiples series thereof I found this article to be useful https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages
Forum Discussion
Where can Lithium cells be obtained? I have a Ryobi 18 V tool battery that will not run a tool despite being charged to 9.5 volts. I am told the circuit in the battery pack doesn't allow current to flow if there is a voltage differential over a tenth of a volt among the 6 cells. One weak cell kills the whole thing.
