About this replacement
Garmin T20 GPS Dog Tracking Collars — 3.7V Li-Polymer Replacement Battery (361-00148-00)
This 3.7V, 1800mAh Li-Polymer battery replaces OEM part 361-00148-00 in the Garmin T20 GPS Dog Tracking Collar. The T20 uses GPS to let owners locate their dogs in real time via the Garmin app. When the original cell degrades, tracking range and update frequency both drop before the battery fails completely.
- T20 collar fit: The T20 runs a single-cell Li-Polymer pack at 3.7V nominal. The replacement matches the OEM connector orientation and BMS communication protocol, so the collar's charge indicator and low-battery alert behave exactly as they did with the factory cell.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the T20 platform. The BMS accepted full charge without triggering an error state, and the collar's GPS module powered on normally through each cycle.
- First GPS acquisition after install: After fitting the new battery, take the dog outside immediately and allow 5–10 minutes for the collar to acquire a GPS fix. Power interruption clears the satellite almanac cache, forcing a cold start — this is normal and only affects the very first lock after a battery swap.
Battery drain on the T20 in rural or low-signal areas
In areas with weak cellular coverage, the T20's onboard radio transmits at higher power to maintain the connection back to the Garmin network. At the same time, the GPS module works harder to hold a lock under tree cover or in valleys. Both subsystems drawing simultaneously is the fastest way to flatten a 1800mAh cell. Switching the collar to a less frequent update interval in the Garmin app reduces the combined load when constant real-time tracking isn't needed.
Collar stops syncing to the Garmin app after a power cycle
After a battery swap or a full power-down, the T20 sometimes drops its registered connection to the Garmin Tracking app. This happens because the collar's cellular or Bluetooth stack re-initialises from scratch and doesn't always complete handshake with the app automatically. Open the Garmin Tracking app, navigate to your device list, and force a manual sync while the collar is within Bluetooth range — typically within 10 metres. If the collar still shows offline, remove it from the device list and re-add it using the collar's device ID printed on the unit.