Suunto Ambit 1 Replacement Battery 3.7V 240mAh PR-382530

Suunto Ambit Series — 3.7V Li-Polymer Replacement Battery (PR-382530)

This is a 3.7V, 240mAh Li-Polymer cell that replaces the original battery in the Suunto Ambit 1, Ambit 2, Ambit 2S, and Ambit 3 GPS watches. It matches the OEM dimensions of 33.00 × 24.35 × 4.20mm, so it seats correctly in the watch housing without modification. Capacity is 240mAh (0.89Wh), identical to the factory specification.

• Ambit 1, 2, 2S, and 3 compatibility: All four models share the same battery bay geometry, connector orientation, and BMS voltage thresholds. The PR-382530 cell works across the range because the protection circuit on each model targets the same 4.2V charge ceiling and 3.0V cutoff floor.
• Bench tested on actual hardware: We ran charge and discharge cycles on the Ambit platform and confirmed the BMS handshake completes without fault codes. The protection circuit tripped correctly at the low-voltage cutoff and released on charge application.
• Post-swap fuel gauge reset: After fitting this cell, place the watch on its charger immediately and run it to 100% before first use. The fuel gauge IC on the Ambit platform loses its reference when the old cell is removed. Without a full charge cycle from near-zero, the gauge will report inaccurate state-of-charge throughout normal use.

Why the Ambit's GPS session accelerates cell drain after a battery swap

A fresh Li-Polymer cell has slightly different internal impedance than a worn one. The Ambit's GPS chipset draws sustained current during active tracking, and on a new cell the voltage response curve is steeper until the cell completes a few full cycles. The fuel gauge IC may interpret this as faster depletion and throttle GPS update frequency as a precaution. Run two or three complete charge-to-discharge cycles through normal GPS use and the gauge will recalibrate to the new cell's actual impedance profile.

Watch not pairing with phone after battery replacement

Removing the battery cuts power to the BLE stack entirely, which clears the active session key the watch holds for its paired device. The phone still shows the watch as paired, but the watch no longer recognises the stored credentials. Go into your phone's Bluetooth settings, forget the Ambit device completely, then re-pair from scratch through the Movescount or Suunto app. The watch should advertise itself within 30 seconds of entering pairing mode.