Oregon Scientific ATC9k Replacement Battery 3.7V 1100mAh

Oregon Scientific ATC9k Action Camera — 3.7V Li-ion Replacement Battery (B-ATC9K)

This 3.7V 1100mAh Li-ion battery replaces the original cell in the Oregon Scientific ATC9k Action Camera. It fits the ATC9k and ATC9k-JWP variants and matches the OEM form factor at 44.99 × 29.85 × 8.59mm. Capacity figure is taken directly from product specification — 4.07Wh total energy.

• ATC9k and ATC9k-JWP compatibility: Both variants use the same battery bay dimensions, connector pinout, and 3.7V nominal voltage rail. The B-ATC9K part number covers both. No adapter or wiring change needed — the cell drops straight into either body.
• Bench tested on actual hardware: We cycled this cell through the ATC9k's BMS at full HD recording load. The protection circuit responded correctly to over-discharge cutoff at the expected low-voltage threshold, and charge acceptance via the camera body completed without error flags.
• First-use charge cycle in the camera body: Run one complete charge cycle through the ATC9k's own USB charging circuit before heavy shooting. The ATC9k's battery indicator maps voltage thresholds to display segments during this first cycle — skipping it can cause the bar to misread remaining charge mid-session.

Why the ATC9k battery indicator drops suddenly during recording

Li-ion cells have a relatively flat discharge curve through most of their capacity, then voltage drops sharply in the final 15–20%. The ATC9k maps a small number of display segments to that entire curve. A replacement cell with a slightly different internal resistance profile can cause the indicator to hold at one bar longer than expected, then cut to zero with no warning. This is a voltage-threshold mapping issue, not a fault with the cell. One full charge cycle inside the camera body recalibrates the BMS reference point for a more accurate readout.

Camera displays no battery icon after installing a replacement cell

The ATC9k runs a basic authentication check when a new cell is inserted — if the BMS doesn't see expected voltage at startup, the camera can display a missing or empty battery icon even on a fully charged replacement. Power cycling the camera two or three times after insertion usually clears the flag. If the icon still doesn't appear, connect the camera to USB power and allow a full charge cycle to complete; the BMS re-initialises against the new cell during charging and should read correctly at 4.2V full charge.