About this replacement
SportDog SD-2525 ProHunter Transmitter — 3.7V Li-Polymer Replacement Battery (SDT00-13794)
This 3.7V, 460mAh lithium-polymer battery fits the SportDog SD-2525 ProHunter handheld remote transmitter. It also fits the SD-1875 Remote Beeper and UplandHunter 1875 series remotes that share the same OEM part number SDT00-13794. Dimensions are 38.50 × 23.80 × 5.50mm — measure your original before installing if you're unsure.
- SD-2525 and SD-1875 platform compatibility: These transmitters share the same battery bay, connector pinout, and BMS handshake protocol across the ProHunter and UplandHunter lines — that's why one cell covers both. Voltage tolerance on this platform is tight at 3.7V nominal; installing an off-spec cell causes the transmitter to show a false low-battery warning or refuse to power on.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the SD-2525 transmitter. The BMS accepted the battery without fault codes, held the protection cutoffs at the expected thresholds, and the transmitter paired normally with a receiver collar across all tested channels.
- First startup after swap: After installing this battery, hold the power button for a full three seconds — the SD-2525 requires a deliberate long-press to boot, not a tap. A short press does nothing and is often mistaken for a dead battery.
Why the SD-2525 transmitter shows low battery immediately after a new cell is installed
The SD-2525 reads battery state through a fuel gauge IC that tracks charge history, not just instantaneous voltage. A freshly installed cell with no cycle history can confuse the gauge into reporting low charge even when the cell is full. Run one complete charge cycle using the OEM charger until the indicator shows full. After that first cycle, the fuel gauge recalibrates and the readout tracks accurately. If the low-battery indicator persists after a full charge, check that the battery connector is fully seated — a partial connection drops the measured voltage below the gauge threshold.
Transmitter powers on but loses signal range to the receiver collar
Reduced RF range from the transmitter is almost always a voltage-sag issue, not an antenna fault. If the cell voltage drops below roughly 3.4V under the transmit load, the radio output stage pulls back power to protect the circuit — and range drops noticeably. This happens most often with aged or partially discharged cells. Charge the battery fully and retest range in an open field; if range restores at full charge but drops off quickly, the cell has degraded capacity and needs replacement.