For the parent devices of dedicated monitors, the battery life ranged anywhere between 6.75 and 12.75 hours. The Wi-Fi options are harder to gauge given that the battery life depends on the kind of device used, whether or not it is being used for other applications simultaneously, and how old the battery is in the device. In general, however, we feel it is relatively safe to say that most will work longer than the best dedicated monitor battery if the device is dedicated for use with the monitor only and is not running other applications simultaneously.
Battery: We wanted a monitor battery that could last overnight, or at least eight hours, without being plugged in. We thought the ideal product would automatically cut off an idle display screen to conserve battery, work at least a few hours unplugged with the screen on, and recharge fairly efficiently. We made a rechargeable battery a requirement. We preferred units designed to connect to power via a standard USB connector, and looked for reports that the baby monitors could reliably charge, recharge, and hold a charge long-term—a disappointingly rare ability in baby monitors.
Rechargeable batteries: Since the camera will most likely stay trained on your bundle of joy, it can remain plugged into AC power. But parent unit displays are designed to be always on and carried with you as you move from room to room. That can drain batteries quickly. Look for a parent unit that runs on rechargeable batteries, so you’re not constantly swapping them out.
If you sleep in the same room as your baby or live in a small enough space that you can always hear or see what your baby is up to, you probably don’t need a monitor. Otherwise, most parents enjoy the convenience a baby monitor provides—instead of needing to stay close to the nursery or constantly checking on your child, you’re free to rest, catch up on Netflix or get things done around the house during naptime. Monitors can also double as a nanny cam to keep an eye on your child and their caretaker.