About this replacement
Garmin Approach S60 / Fenix 5 / Forerunner 935 — 3.7V Li-Polymer Replacement Battery (361-00097-00)
This is a 3.7V, 230mAh Li-Polymer cell that replaces OEM part 361-00097-00. It fits the Garmin Approach S60, Fenix 5, and Forerunner 935 GPS smartwatches. Physical dimensions are 28.20 × 22.00 × 4.10mm — measure your existing cell before ordering if you are unsure.
- Approach S60, Fenix 5, and Forerunner 935 compatibility: All three watches share the same cell footprint, connector pinout, and BMS handshake protocol. Garmin standardised this across the platform during that product generation, so one cell covers all three models without modification.
- Bench tested on actual hardware: We cycled this cell on a Fenix 5 unit and confirmed the BMS accepted the new cell without fault codes. The fuel gauge IC re-initialised correctly after a full charge cycle from near-zero following installation.
- Post-swap charge requirement on Garmin GPS watches: After fitting this cell, place the watch immediately on its magnetic charger and run it to 100% before first use. The fuel gauge IC on these Garmin platforms loses its reference point when the cell is disconnected. Without a full charge cycle from near-zero, the percentage reading will be inaccurate and the watch may shut down unexpectedly at what it reports as 20–30%.
Why the Approach S60 and Forerunner 935 drain a new cell faster in the first week
A fresh Li-Polymer cell has slightly different internal impedance than a well-cycled original. The Garmin power management IC adjusts its draw profile over the first several charge-discharge cycles as it characterises the new cell. GPS and heart rate sensor current draw may appear higher than expected during this break-in period. This normalises after approximately five full cycles — no action is required.
Magnetic charge contacts not connecting after reassembly
If the watch shows no charging indicator when placed on its puck after a battery swap, the back cover has likely shifted the internal charge contact pad by a fraction of a millimetre. Remove the back cover, inspect the contact pad alignment, and reseat it before refastening. Clean the rear case contacts and puck pins with isopropyl alcohol if corrosion is present. Once aligned correctly, the watch should show a charging animation within 10 seconds of contact — if it does not, verify the puck is outputting voltage before assuming a cell fault.