Does mAh matter when replacing a battery?

Answer 1

mAh is a measure of the amount of charge stored in a cell or battery (set of cells). One (1) Ah is the equivalent of 1000mAh, and so the statement can be made that a cell with 2000mAh of stored charge can supply a device drawing one (1) mA for 2000 hours -- before needing replacement or recharge.

It also means 1/1000*C/s*3600s.(1 milli= 1/1000, C=Unit for charge, s=seconds) which finally means that a battery rated 1mAh can hold a charge equal to 3.6 coulombs of charge.

Answer 2

Maybe, maybe not. There are several ways to define battery life:

• Time the battery will hold charge before needing recharge.
• Number of charge/discharge cycles before battery will no longer charge.
• Shelf life (when not used).
• etc.

Some correlate to mAh rating, some don't.

Answer 3

Yes it is one of the basic parameters of a battery. Batteries are rated in Volt Amps, for instance most cell phones use a 3.6 volt battery; given that voltage will last X amount of time at this amperage (rated in mAh - Milla-Amp Hours; amp hours). To translate, a battery at 3.6V and 1200mAh would last 120 hours on standby in Cellphone X, but if you put a 1000mAh battery in the unit it would only last 100 hours. If the mAh is too low the voltage drop would cause the unit to not function (Given as E/(I*R) ).

Batteries are not rated in Volt Amps. They are defined by their terminal voltage and their capacity. The capacity is the product of time and current.

The capacity of small batteries and cells is given in mAh (milliampere-hours); a large battery's capacity in Ah (ampere-hours).