Why Rechargeable Batteries Use 1.2V Voltagefleeting
- External reference: https://learn.adafruit.com/li-ion-and-lipoly-batteries/voltages
- External reference: https://electronics.stackexchange.com/questions/219457/why-rechargeable-batteries-use-1-2v
Why rechargeable batteries use 1.2V
1.2V is only nominal voltage. 1.2V was a round number close enough to the typical voltage of those three chemistries and thus became the voltage on the label. However, every battery chemistry has different characteristics including voltage across a discharge cycle and open-circuit voltage.
Well designed electronics powered by AAA/AA/C/D cells should be designed to work down to well under 1.0 Volts, ideally down to about 0.8V to extract the most energy form the cell - any cell chemistry type. When this is the case, it doesn’t matter that NiCad & NiMH rechargeable cells have that lower terminal voltage, they’ll still deliver all their energy.
Back in the old days, though, when a lot of electronics gadgets weren’t designed to operate to < 1.0 V, the gadget fitted with NiCad rechargeable batteries would malfunction &/or shut off prematurely, and gadget manufacturers would warn customers not to use them, and to use non-rechargeable carbon/alkaline cells
almost all lithium polymer batteries are 3.7V or 4.2V batteries
means is that the maximum voltage of the cell is 4.2v and that the “nominal” (average) voltage is 3.7V
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
Important Note! When charging batteries you must make sure that the charger voltage is less than or equal to the battery voltage. For the best battery performance/life you should have them matched