About this replacement
ACTIVEON CX / CX HD / CX Gold — 3.7V Li-Polymer Replacement Battery (ACA01RB)
This is a 3.7V, 600mAh Li-Polymer replacement cell for the ACTIVEON CX, CX HD, and CX Gold action cameras. It matches the OEM part number ACA01RB and fits the compact battery bay on all three camera variants. Carry a spare and swap in the field rather than waiting for a full charge cycle between shoots.
- CX, CX HD, and CX Gold compatibility: All three models share the same physical bay dimensions, connector pinout, and 3.7V nominal voltage rail — which is why a single cell covers the full CX lineup without modification.
- Bench tested on actual hardware: We cycled this cell through the CX body and confirmed the BMS accepted the cell on the first charge. Voltage held steady across standard recording and photo burst modes with no unexpected cutoffs.
- First-install charge cycle: Insert the new cell and run one full charge via the camera body or OEM charger before heavy use. Some action camera BMS firmware maps the battery-remaining indicator against a charge curve it only calibrates during the first in-body cycle — skipping this step can cause the indicator to read inaccurately from the start.
Why the ACTIVEON CX battery indicator drops sharply near 30%
The CX uses a voltage-threshold method to estimate charge remaining rather than a fuel-gauge IC. Li-Polymer cells have a flat discharge curve through the mid-range, then voltage drops quickly at the low end. A new replacement cell may have a slightly different discharge curve than the original, which causes the indicator to fall faster than expected once it crosses the lower voltage threshold — typically around 3.5V. One full charge-discharge cycle in the camera body usually tightens the mapping.
ACTIVEON CX showing a dead battery icon immediately after inserting a charged replacement
This is a BMS authentication check the camera runs on insertion — it measures resting voltage before accepting the cell. If the replacement arrived partially discharged from storage, the resting voltage may sit below the camera's acceptance threshold even though the cell is not depleted. Connect the camera to its OEM charger immediately after inserting the cell without powering on first. Once the charger initiates and voltage rises above 3.7V, the camera body will recognise the cell and the icon will clear.