Hi, welcome to Android Forums.
A Google search provided this info :-
"mAh
Milliamp Hours.
A unit for measuring electric power over time. mAh is commonly used to describe the total amount of energy a battery can store at one time.
A battery rated for more mAh will power a phone for a longer amount of time, given the same usage pattern. The trade-off is that batteries with more mAh are generally also physically larger.
More technically, a higher mAh rating means the (fully-charged) battery can power a device that consumes more power and/or for a longer amount of time before becoming depleted and needing to be re-charged. For example, a battery rated at 1500 mAh can power a device drawing 100 milliamps for 15 hours, or a device drawing 150 milliamps for 10 hours."
If your phone is in standby, the current drawn will be minimal. If you're surfing the web, screen on, wifi on, maybe listening to music as well, the current drawn will be quite high.
Hope this helps.
