Built in batteries

We received a Ring 2 doorbell that has a built in battery as a Christmas gift. It was installed with the battery fully charged and hardwired to the old bells connections. After only a month we received a low battery message. Upon researching this found out lithium batteries don't last long when it's cold. As the battery is built in I'll have to disconnect the hard wires connected to the back of the doorbell every time the battery needs charging. The only videos I can find about Ring doorbells show the removable batteries and not the headache that comes with built in.