About this replacement
Asus ROG Spatha X / Gladius II — 3.7V Li-Polymer Replacement Battery (FT902536P)
This 3.7V, 800mAh Li-Polymer battery replaces the internal rechargeable cell in the Asus ROG Spatha X, ROG Gladius II, and ROG Spatha RF wireless gaming mice. The original FT902536P cell is a slim pouch-format pack measuring 44.50 × 23.00 × 10.50mm — an exact physical match is critical for reassembly. Capacity is rated at 800mAh (2.96Wh), matching the OEM spec.
- ROG Spatha X, Gladius II, and Spatha RF fitment: All three models share the same internal battery bay dimensions and connector pinout, which is why they run the same FT902536P cell. Swapping between these platforms carries no electrical risk — the BMS on each mouse reads the same voltage profile.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a Spatha X unit. The onboard BMS accepted the pack without fault codes, balanced charge termination landed at 4.20V, and cutoff triggered cleanly at the low-voltage threshold without dropping the USB connection mid-session.
- Connector orientation on the Gladius II: The Gladius II routes the battery connector toward the rear of the shell. Plug the lead in before seating the cell flat — trying to connect it after the cell is pressed down risks stressing the solder points on the PCB.
Why the ROG Spatha X RGB draw accelerates battery aging
The Spatha X runs per-zone RGB lighting continuously in wireless mode, and that draw sits on top of the 2.4GHz polling load. An 800mAh cell handling both loads cycles deeper per session than a mouse without lighting. Deeper cycles per charge accelerate capacity fade in Li-Polymer cells — the chemistry tolerates shallow cycles far better than full-depth ones. If you game with RGB at full brightness daily, the original cell typically shows measurable capacity loss within 18 months. Reducing RGB brightness in Armoury Crate extends the replacement cell's service life noticeably.
Mouse pointer stuttering or lag after battery replacement
Stuttering after a battery swap is usually a voltage issue, not a pairing issue. If the new cell shipped partially discharged, the mouse's 2.4GHz transmitter may not have enough headroom to maintain a stable polling rate — the firmware throttles the radio before it drops the connection entirely. Charge the mouse fully before testing movement; full charge brings the cell to 4.20V and gives the transmitter full operating headroom. If stuttering persists after a confirmed full charge, re-plug the USB receiver into a different port to rule out a host-side dropout.