Cell phone

[woodchip]

Cell phone battery is warm even when the phone is off, Either battery is wearing out as it now only holds charge for less than a day (before it would hold charge for 2 days or more) or something is using it to transmit someplace (like a app?). Any idea if I'm correct and what do you think is going on.?

[Krom]

Typical cell phone batteries are lithium-ion polymer, they gradually lose capacity over time and start degrading from the moment they are manufactured. So as a rule the older the battery is, the less charge it can hold. If this battery is more than a couple years old, it is probably just age, but it could be compounded by some application on the phone preventing shutdown/sleep. Otherwise batteries will typically warm up while charging, especially if it is a higher rate charger. You could also backup all your important data from the phone, then do a factory wipe/reset and see if it persists in an original state.

Warming up while discharging can also happen, but more likely the phone electronics are generating the heat since in order to make a battery warm up from discharge you have to draw it down at an enormous rate (meaning going from full charge to empty in minutes), so that is less likely.

Otherwise, li-poly batteries are known to explode under certain conditions, the easiest way to tell would be to remove the battery entirely and let it sit for 30+ minutes, if it remains warm for an extended period even while removed from the device then dispose of it immediately in a fire safe container.

[woodchip]

Thanks Krom. Guess it is time to get a new battery. Fairly cheap on Amazon.