Cardo G4 Replacement Battery 3.7V 800mAh BAT00002

Cardo G4 / G9 / Scala Rider Series — 3.7V Li-Polymer Replacement Battery (BAT00002)

This 3.7V, 800mAh Li-Polymer cell replaces the original battery in the Cardo G4, G9, G9x, and Scala Rider G4 wireless motorcycle headsets. It matches the OEM dimensions (49.20 × 19.50 × 9.20mm) and connector, so it seats without modification. When the original cell degrades and the headset stops holding charge, this restores normal operation.

• G4, G9, G9x, and Scala Rider G4 fit: These models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers the full group — no variant-specific wiring differences across the listed models.
• Bench tested on actual hardware: We ran charge and discharge cycles through the BMS and confirmed the protection circuit trips correctly at low-voltage cutoff. The cell accepts a full charge without thermal event and the BMS clears the fault state as expected on the Cardo charging dock.
• First charge on the Cardo dock: Place the headset in its charging dock and run a complete charge cycle before your first call. The Cardo dock logs the new cell during that first cycle — until it does, the on-device talk-time indicator will read inaccurately.

Why the G4 cuts out mid-transmission on a fresh battery

The G4 draws current from two loads simultaneously — the audio amplifier and the Bluetooth radio. During an active intercom or call, that combined draw creates brief voltage sag at the cell terminals. On a degraded original battery, this sag trips the low-voltage cutoff and the headset drops the connection. A new cell with full capacity handles the combined load without the terminal voltage dipping below the BMS threshold, so the cutout stops.

Base station shows full charge but headset dies after a few minutes

A new Li-Polymer cell ships at storage voltage — typically around 3.6–3.7V — not at full charge. The dock's charge indicator can show complete before the cell has actually reached 4.2V if the first cycle is interrupted or the dock misreads the incoming voltage state. Pull the headset from the dock, power it off completely, reseat it, and let it run an uninterrupted charge cycle to 4.2V before use. After that first full cycle, the dock reads and charges the cell correctly.