Since beacons use Bluetooth Low Energy, most people think that a beacon can run on any battery for an indefinite amount of time. While Bluetooth Low Energy was designed for long life on small batteries, this is not true for every Bluetooth Low Energy device. Some Bluetooth Low Energy devices may not broadcast at all, and only listen occasionally for a connection. Others may broadcast only every few minutes and go into deep hibernation in-between broadcasts.
Beacons that are “in-spec” with the iBeacon protocol broadcast 10 times a second. The majority of energy used by Bluetooth devices is used when the device is broadcasting, and since beacons broadcast multiple times a second, this broadcast rate can cause significant battery drain, requiring the batteries to be replaced every few weeks. Reducing the broadcast rate can improve battery life in the beacon, but will make the beacon out of spec, have a sub-optimal user experience, and may break future compatibility.
Having a beacon that has AC power is an easy way to have a beacon that will continue to broadcast for years to come. If there is not AC power available, consider a beacon with a larger battery that will last months between battery replacement.
Looking for a great AC powered beacon? Check out http://twocanoes.com/bleu. Plug in our AC powered beacon and they never need a battery replaced.
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