Battery Failure Indicators

Battery Failure Indicators
1, The usable time after recharging is shortened.
2, The battery becomes unusually warm during a recharge cycle.
3, The battery becomes unusually warm during phone use.
4, The battery case often is swollen. This is detectable by feeling and viewing the inside/phone-side of the battery case. Also, when the battery is placed inside/phone-side down on a flat, smooth surface, it will rock and will sustain a spin motion. 5,The case of a healthy battery is flat and will not sustain a spin motion.
5, The battery develops a hard spot. This is detectable on the inside/phone-side surface of the battery by gently pinching about the surface between one's fingers.

How to Lengthen the Life of Batteries Without Recharging
Take the batteries out of the socket.
Place the batteries between your hands.
Rub your hands together as if you were warming them on a snowy day. Almost any chemical reaction proceeds faster when warmer.
Place the batteries back in the socket.

If you're at home, placing them in the refrigerator is supposed to help, and sometimes it does.
Storing the batteries in the fridge will help lengthen the shelf life, and thus their life when you finally use them.
It is best to replace older rechargeable Ni/Cd batteries as their ability to store electrical energy decreases with age and use.
If you only need a little bit of battery life, then shaking it may give them that last little bit of juice. (This will only work for a very short time.)

Note
Do not install a battery backwards as hydrogen can build and damage can result.
Do not leave a battery in a device if you do not intend to use it for an extended amount of time as the battery could leak and cause damage to the device.