About this replacement
GolfBuddy Voice X — 3.7V Li-Polymer Replacement Battery (DR652525)
The DR652525 is a 3.7V 400mAh Li-Polymer cell for the GolfBuddy Voice X GPS golf watch. It fits the Voice X and 2ALG4 VoiceX variants. Swap this cell when the original no longer holds a charge through a full round.
- Voice X and 2ALG4 VoiceX compatibility: Both models run the same 3.7V power rail and share the DR652525 footprint — 26 × 25 × 6mm. The BMS connector pinout and cell dimensions are identical across these two variants, so one cell covers both.
- Bench tested on actual hardware: We cycled this cell through charge and GPS-active discharge on the Voice X platform. The BMS accepted the new cell cleanly, with no handshake errors or low-voltage cutoff trips during the test cycle.
- Post-swap fuel gauge reset: After fitting this cell, place the watch on its charger immediately and run a full charge to 100% before first use. The fuel gauge IC on the Voice X cannot set its reference point without a complete charge cycle from near-zero following a cell swap — skipping this step causes the percentage readout to behave erratically.
Why the Voice X GPS lock pulls harder on a new cell than the old one did
A degraded Li-Polymer cell develops higher internal impedance over time. The GPS module draws a spike of current during satellite acquisition, and an aged cell sags under that load — so the watch throttles GPS update frequency to compensate. A fresh DR652525 has lower impedance, so the GPS module runs at full acquisition current without triggering the BMS undervoltage threshold. During the first week after a swap, the fuel gauge may read slightly inconsistently while it learns the new cell's discharge curve — this normalises after three to five full charge cycles.
Watch showing 0% and refusing to power on after cell swap
This is a fuel gauge IC problem, not a faulty cell. The MAX or similar coulomb-counter IC on the Voice X loses its stored reference the moment the old cell is disconnected. With no reference, it reads the new cell's resting voltage as 0% and the watch protection circuit refuses to boot. Connect the watch to its charger immediately after reassembly — the charger line forces the IC to reinitialise and accept the cell. Charge to 100% before attempting to power on; once the gauge completes that first full cycle, the readout stabilises at the correct state of charge.