How Long Do Android Batteries Last. Batteries are rechargeable and must be plugged in after the drain for the phone to operate. On edge maybe in 12 hours under constant usage.

How Long Does Your Android Battery Last When Charged Full by nmreports. Typically a modern phone batterys lithium-ion lifespan is 2 3 years which is about 300 500 charge cycles as rated by manufacturers. As you charge and discharge your battery it degrades and over time you get less battery life from a full charge.
Most Android phones Ive come across have either of these or both accidentally left on.
Also look for a battery with an extended full-replacement warranty. Two years is not unheard of but its not very common. Quality batteries offer free replacement for three or more years if there is a problem within that period. This Is How Long Smartphone Batteries Should Last.
