Golf Buddy PT4 GPS Replacement Battery 3.7V 2100mAh

Golf Buddy PT4 / Platinum 4 — 3.7V Li-ion Replacement Battery (LI-F03-01)

This is a 3.7V, 2100mAh Li-ion cell that replaces part number LI-F03-01 in the Golf Buddy PT4 and Platinum 4 handheld golf GPS navigators. It also fits the DSC-GB600 and GB3-PT4 variants that share the same housing and connector. Swap it in when the original cell no longer holds enough charge to complete a round.

• PT4 and Platinum 4 platform fit: These models share an identical battery bay, connector pinout, and BMS communication protocol — the same cell covers all four listed model numbers without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a PT4 unit. The BMS accepted the cell without fault flags, voltage regulation held steady across the charge curve, and the protection circuit tripped correctly at the low-voltage threshold.
• Cold-start satellite acquisition after swap: After fitting this cell, power the device on outdoors and let it acquire a satellite fix before heading to the first tee. A full power interruption clears the GPS receiver's ephemeris cache, so first fix after a battery swap can take 5–10 minutes. Subsequent power cycles return to a warm-start fix under a minute.

Golf Buddy PT4 shutting off without warning mid-round

The PT4 reads battery percentage from a fuel gauge calibrated to the original cell's discharge curve. A degraded or replaced cell can shift that curve enough that the device reports 20% remaining and then cuts off seconds later. The shut-off threshold is a hard voltage floor — when the cell drops below roughly 3.2V, the BMS disconnects before the display shows a low-battery alert. After fitting this replacement, run two full charge-to-discharge cycles on the course so the fuel gauge re-calibrates to the new cell's curve and percentage readings stabilise.

Saved courses and round data missing after battery replacement

The PT4 stores course data in flash memory, which is non-volatile and survives a battery swap. However, session state — current round in progress, hole position, and any unsaved score data — is held in RAM and is lost the moment power is removed. If a round was active when the old battery died, that session data is gone. Complete and save any active round before removing the battery, then sync to the Golf Buddy app to back up course data before the swap.