About this replacement
Asus ROG Strix Fusion 700 — 3.7V Li-Polymer Replacement Battery (FT603048P)
This 3.7V, 900mAh Li-Polymer cell replaces the original battery in the Asus ROG Strix Fusion 700 wireless gaming headset. It restores full wireless audio function when the factory cell no longer holds adequate charge. Dimensions are 50.30 × 29.60 × 6.00mm — confirm these against your existing cell before fitting.
- ROG Strix Fusion 700 fit: The Fusion 700 runs a single Li-Polymer cell on a 3.7V rail shared across the DECT radio module and the audio DSP. Both draw from the same cell simultaneously, so the BMS must handle combined current spikes without tripping. This cell meets that profile.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Fusion 700 platform. The BMS completed handshake without error, and the base station accepted the pack without showing a charge fault.
- First-charge protocol for the Fusion 700: Seat the headset in the base station and run a full uninterrupted charge cycle before use. The Fusion 700's base needs to log the new cell before the on-screen charge indicator reads accurately — skip this step and the display will misreport state of charge.
Why the Fusion 700 cuts out mid-session on a new battery
The Fusion 700 pulls current from two loads at once — the DECT radio and the audio DSP. During heavy wireless activity, combined draw spikes briefly above the resting load. A new cell not yet through its first full cycle carries higher internal resistance, which causes a momentary voltage sag. The BMS reads that sag as a low-cell event and shuts the headset down to protect the cell. Run two to three full charge-discharge cycles and the internal resistance drops, reducing sag under peak draw.
Base station shows full charge but headset shuts off after short use
A replacement cell shipped in storage state typically sits around 3.6–3.7V — enough for the base to read it as charged, but not a true full cycle. The base station's charge indicator trips off voltage alone on the first insertion, not capacity. The headset then runs down quickly because the cell was never brought to a full 4.2V charge from a rested state. Place the headset in the base for a complete uninterrupted charge cycle starting from power-off, then verify the cell reaches 4.2V before first use.