Most electronic beacons run on small coin cell batteries, though the best power source depends on the type of beacon, where it’s installed, and how long you need it to last. Bluetooth Low Energy (BLE) beacons, emergency locator beacons, and industrial beacons each have different power demands and different solutions available.
Coin Cell Batteries for BLE Beacons
The majority of commercial Bluetooth beacons use one of four battery types, each with a different capacity:
- CR2032: 250 mAh, the smallest and most common option
- CR2450: 500 mAh, a mid-range choice
- CR2477: 1,000 mAh, double the CR2450
- AA batteries (2 or 4 pack): 2,200 to 6,000 mAh depending on chemistry and quantity
A CR2032 is the same flat battery you’d find in a watch or car key fob. It’s cheap and widely available, but its small capacity means it works best for beacons that broadcast infrequently or at low power. For deployments where you need years of battery life without maintenance, stepping up to a CR2477 or AA-powered beacon makes a significant difference. Lithium AA batteries outperform alkaline ones, delivering roughly 3,000 mAh per cell compared to 2,200 mAh for alkaline.
How Settings Affect Battery Life
Two settings have an outsized effect on how quickly a beacon drains its battery: the advertising interval (how often it broadcasts) and the transmit power (how strong the signal is).
Increasing the advertising interval from 100 milliseconds to 1 second drops average current consumption by about 93%. In concrete terms, a beacon broadcasting every 100 ms at full power draws around 419 microamps on average. Stretch that interval to once per second and the draw falls to just 21.5 microamps. That’s the difference between a battery lasting months versus lasting years.
Transmit power matters too. Reducing it from 8 dBm (the default on many chipsets) to 0 dBm cuts the current roughly in half at the same broadcast rate, from 419 microamps down to 190. The tradeoff is range: lower power means a shorter detection distance. For a beacon mounted at a retail checkout counter where phones are within a few feet, you can safely lower the transmit power. For a beacon covering a warehouse aisle, you’ll want to keep it higher and budget for more frequent battery swaps.
If you’re deploying multiple beacons, dialing in these two settings before installation is the single most effective way to extend battery life across your entire fleet.
Cold Weather and Battery Performance
Temperature is a hidden factor in beacon power planning. Lithium coin cells lose capacity dramatically in cold environments. At -20°C (-4°F), a standard graphite-based lithium cell retains only about 12% of its room-temperature capacity. That means a CR2032 rated at 250 mAh could effectively deliver as little as 30 mAh in a freezing warehouse or outdoor winter deployment.
Newer battery chemistries handle cold better. Some lithium-ion cells using tin oxide anodes retain around 71% of their capacity at -20°C, a massive improvement. If your beacons will operate in sub-zero conditions, choosing a battery chemistry rated for low temperatures, or housing the beacon in an insulated enclosure, is essential. Otherwise you’ll find yourself replacing batteries far sooner than the manufacturer’s estimates suggest.
Hardwired Power for Permanent Installations
For beacons that need to run indefinitely without battery changes, Power over Ethernet (PoE) eliminates the battery entirely. PoE delivers both data and electrical power through a single Ethernet cable, which simplifies wiring considerably.
The basic PoE standard (IEEE 802.3af) provides up to about 13 watts at the device, which is far more than any BLE beacon needs. Higher-tier standards deliver 25 to 71 watts, though those are designed for devices like security cameras and wireless access points. For beacons, the base standard is more than sufficient.
PoE-powered beacons are common in hospitals, airports, and large retail spaces where hundreds of beacons would create a maintenance burden if they all ran on coin cells. The upfront cost of running Ethernet cable is higher, but the ongoing cost of battery replacement drops to zero. You also get more consistent signal strength since the beacon never enters a low-battery state where its transmit power degrades.
USB and Solar Options
Some beacon manufacturers offer USB-powered models that draw from a standard 5V USB adapter. These work well in settings where a power outlet is nearby but running Ethernet cable isn’t practical, like a conference room or tradeshow booth. A USB beacon paired with a small solar panel and battery pack can also work for semi-permanent outdoor installations where neither wired power nor frequent battery swaps are feasible.
Solar-powered setups need careful sizing. A BLE beacon drawing 20 to 400 microamps is extremely low-power, so even a small solar cell with a rechargeable lithium battery can keep one running through cloudy days. The key is matching the panel and battery capacity to the worst-case scenario for your location’s sunlight hours.
Emergency Locator Beacons
Emergency beacons, such as personal locator beacons (PLBs) and aviation emergency locator transmitters (ELTs), follow strict regulatory rules for battery management. Under U.S. federal aviation regulations, the battery in an ELT must be replaced when the transmitter has been in use for more than one cumulative hour, or when 50% of the battery’s useful life has expired, whichever comes first. The expiration date must be visibly marked on the outside of the transmitter.
These beacons typically use lithium battery packs specifically designed for their transmitter model, not off-the-shelf coin cells. Replacing them with anything other than the manufacturer-specified battery can void the device’s certification. Some marine beacons use water-activated batteries that remain inert during storage and are exempt from the 50% replacement rule since they don’t degrade on the shelf.
If you own a PLB for hiking, boating, or backcountry travel, check the battery expiration date printed on the unit at least once a year. An expired battery in an emergency beacon defeats its entire purpose.