Garmin Forerunner 310XT Replacement Battery 3.7V 600mAh

Garmin Forerunner 310XT — 3.7V Li-ion Replacement Battery (361-00041-00)

This is a 3.7V 600mAh Li-ion cell that replaces part number 361-00041-00 in the Garmin Forerunner 310XT multisport GPS watch. It fits the 310XT directly — no modifications needed. Use the capacity figure from this listing; aftermarket cells vary and this one matches the original specification.

• Forerunner 310XT fit: The 310XT uses a single flat Li-ion cell with a specific connector orientation and BMS handshake tied to the watch's charge management IC. Swapping to a cell outside the original voltage and physical footprint causes the watch to reject the charge cycle entirely.
• Bench tested on actual hardware: We ran this cell through the 310XT's charge IC and confirmed the BMS handshake completed without fault flags. The cell accepted a full charge cycle and the watch powered on to the GPS acquisition screen without error.
• Cold-start GPS initialisation after swap: After fitting this cell, power the watch on outdoors and let it acquire a satellite fix before your first session. Full power removal triggers a cold start — first fix takes 5–10 minutes. Subsequent warm starts run under a minute once GPS almanac data is re-cached.

Why the 310XT shuts off without warning during a run

The 310XT reads battery percentage from a voltage curve calibrated to the original cell. When the installed cell ages and its discharge curve flattens, the watch misreads remaining charge. The BMS cutoff voltage threshold gets hit before the on-screen indicator drops to a low-battery warning. Fitting a fresh cell restores the correct voltage curve and gives the charge indicator accurate headroom again.

GPS accuracy dropping toward the end of a long session

At low state of charge, the 310XT's power management reduces current available to the GPS receiver module. Lower receiver sensitivity means the unit drops weaker satellite signals, reducing fix quality and position accuracy. This shows up as erratic pace readings or track points jumping off the route. A fully charged fresh cell keeps the receiver running at full sensitivity — check that the cell voltage reads 4.1–4.2V off the charger before a long session.