About this replacement
Garmin Sport PRO Handheld Transmitter — 3.7V Li-ion Replacement Battery (361-00056-13)
This 3.7V, 750mAh Li-ion cell replaces the OEM battery in the Garmin Sport PRO Handheld Transmitter. The Sport PRO is a dog training remote that sends commands to compatible Garmin e-collar receivers. When the original cell loses capacity after repeated charge cycles, this direct replacement restores full transmitter function.
- Sport PRO transmitter fit: The Sport PRO handheld uses a fixed-voltage 3.7V Li-ion cell with specific physical dimensions — 47.00 x 34.20 x 4.60mm. The BMS in the transmitter monitors cell voltage and will refuse to power on if the cell drops below the low-voltage threshold, which is why a depleted OEM cell often appears completely dead rather than weak.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Sport PRO unit, confirming the BMS accepted the cell without fault codes and that charge termination triggered correctly at full capacity.
- First outdoor use after install: After fitting the new battery, take the transmitter and collar outside and allow a full GPS cold-start acquisition before beginning a training session — a power interruption resets the GPS almanac, and the first fix after swapping the battery takes noticeably longer than normal warm-start updates.
Why the Sport PRO transmitter shows a full charge but the collar stops responding mid-session
A Li-ion cell that has aged beyond its usable cycle life can still report a high state of charge to the BMS while delivering almost no current under load. The Sport PRO transmitter draws a burst of current each time it sends a signal to the collar receiver. An internally degraded cell voltage sags under that burst load, and the BMS cuts output before the signal completes. Replacing the cell restores the capacity headroom needed to sustain those transmission bursts cleanly.
Transmitter not powering on after battery replacement
If the Sport PRO shows no response after fitting this battery, the replacement cell may have shipped in a deep-discharge protection state — common with Li-ion cells stored long-term below 2.5V. Connect the transmitter to its USB charger for at least 15–20 minutes before pressing the power button. The BMS needs to see a trickle charge input before it will re-enable the output rail. If the charge indicator does not illuminate within five minutes of connecting, check the connector seating and confirm cable continuity — the cell output voltage at rest should read at or above 3.0V.