Garmin EDGE 1040 Replacement Battery 3.7V 1800mAh

Garmin EDGE 1040 / inReach Messenger — 3.7V Li-Polymer Replacement Battery (361-00135-01)

This is a 3.7V, 1800mAh Li-Polymer replacement cell for the Garmin EDGE 1040 cycling GPS computer and the inReach Messenger. Both devices use OEM part number 361-00135-01. Fit the same physical cell — 48.00 × 42.60 × 6.20mm — with the same connector and BMS interface.

• EDGE 1040 and inReach Messenger compatibility: Both devices share the 361-00135-01 cell because they run the same 3.7V power rail and use an identical connector pinout. The BMS handshake protocol is the same across both platforms, so the replacement cell communicates charge state to each device without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the EDGE 1040. The BMS reported accurate state-of-charge throughout, with no false low-battery triggers or premature cutoff events during GPS-active testing.
• First satellite fix after fitting: After fitting this cell, power the EDGE 1040 fully on outdoors before your ride. A full power interruption clears the satellite almanac cache, so the device performs a cold start — expect 5–10 minutes for the first fix versus under a minute for subsequent warm starts once the almanac rebuilds.

GPS accuracy reduced at low battery on the EDGE 1040

When battery voltage drops toward the lower end of the 3.7V nominal range, the EDGE 1040 reduces GPS receiver sensitivity to conserve power. This shows up as a wider track scatter on the recorded ride file — switchbacks look rounded and elevation graphs develop staircase artefacts. The receiver is still locking onto satellites, but with fewer signals processed. Keeping the cell above 3.5V under load maintains full receiver sensitivity and cleaner track data.

EDGE 1040 shuts off without warning at the start of a descent

This happens when the on-screen battery indicator reads 10–15% but the device cuts out immediately. An aged or deeply discharged cell develops higher internal resistance — under the momentary load spike of the GPS receiver processing rapid altitude and speed changes, terminal voltage drops below the BMS cutoff threshold faster than the indicator updates. The device shuts down before the visual warning fires. After fitting a fresh cell, do one full charge cycle to 4.2V so the fuel gauge recalibrates its cutoff curve to the new cell's actual capacity.