MyPhone Active Sport FHD Replacement Battery BR-01 3.7V 900mAh

MyPhone Active Sport FHD — 3.7V Li-ion Replacement Battery (BR-01)

This is a 3.7V 900mAh Li-ion cell (OEM part BR-01) for the MyPhone Active Sport FHD action camera. It slots into the same battery bay as the original and connects to the same BMS rails. Capacity is rated at 3.33Wh — identical to the factory spec.

• Active Sport FHD fitment: The Active Sport FHD uses a compact single-cell bay with a specific connector pitch and cell footprint of 32.77 × 29.16 × 10.89mm. This cell matches those dimensions exactly, so the door closes flush and the BMS handshake completes on power-on.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, monitoring BMS acceptance and cutoff thresholds. The protection circuit trips at the correct low-voltage point, and the camera recognised the cell without throwing an error on first boot.
• First-cycle charging on the Active Sport FHD: Run the first full charge from inside the camera body using the OEM cable, not a third-party USB charger. The Active Sport FHD's BMS maps battery-remaining percentages during that initial in-body charge — skipping it can cause the indicator to read inaccurately for the first several cycles.

Why the Active Sport FHD drains faster during continuous 1080p video than photo mode

Photo capture draws a short burst of current — sensor read, write to card, done. Continuous video at FHD keeps the image sensor, processor, and storage controller all pulling current simultaneously without pause. On a 900mAh cell, that combined sustained draw is significantly higher than single-shot use. Switching to a lower frame rate or disabling the Wi-Fi transfer function during recording reduces that draw and extends each charge cycle.

Battery percentage jumping or stalling on the Active Sport FHD display

This happens when the camera's voltage-threshold map doesn't yet match the new cell's discharge curve. The original BMS calibration was built around the aged characteristics of the factory cell, so a fresh replacement with a steeper discharge profile can cause the indicator to skip or freeze at certain percentages. Perform two full charge-discharge cycles through the camera body — do not pull the battery mid-cycle. By the third cycle, the indicator typically tracks the actual cell voltage within a few percentage points.