Datasheet

Voltages

Depending on the design and chemistry of your lithium cell, you may see them sold under different nominal "voltages".

For example, almost all lithium polymer batteries are 3.7V or 4.2V batteries. What this means is that

the maximum voltage of the cell is 4.2v and that the "nominal" (average) voltage is 3.7V. As the battery is used, the

voltage will drop lower and lower until the minimum which is around 3.0V. You should see the number 3.7V written on

the battery itself somewhere.

For example, here is a profile of the voltage for a 'classic' 3.7V/4.2V battery. The voltage starts at 4.2 maximum and

quickly drops down to about 3.7V for the majority of the battery life. Once you hit 3.4V the battery is dead and at 3.0V

the cutoff circuitry disconnects the battery (more on that later.