Why a battery loses its power when not in use?

[Frankseo]

Q:Why a battery loses its power when not in use?
A:A batteryloses 1% of its power every 3 to 4 days when not in use. It's normal cause the environment is not fully insulated.

MOD EDIT - Removed spam link

[RichardP]

Q:Why a battery loses its power when not in use?
A:A battery loses 1% of its power every 3 to 4 days when not in use. It's normal cause the environment is not fully insulated.

Well thats a bit of a misnomer. Although you perceive the device to be OFF, its really in a deep sleep monitoring for keypresses or perhaps even clock ALARM. This uses energy, and coupled that batteries will discharge due to internal resistance - they will lose energy even when 'Nothing' appears to be happening.

[quatermass]

The battery is Lithium Ion. This is normal.

Lithium ion batteries start to discharge as soon as it is charged.

They also degrade over time. After 2-3 years, it'll have lost its ability to keep its charge.

So always buy a new battery that is at most only 6 months old. A dodge by some cheap battery sellers is to sell on their old batteries that have been lying on a shelf for a year...