About this replacement
Stryker Casque Chirurgical Flyte — 7.4V Li-ion Replacement Battery (0408-660-000)
This is a 7.4V, 5200mAh lithium-ion battery for the Stryker Casque Chirurgical Flyte surgical headlight system and the Flyte Personal Protection System. It replaces OEM part 0408-660-000. The battery mounts to the worn unit and powers the surgical headlamp throughout a procedure.
- Casque Chirurgical Flyte and Flyte Personal Protection System: Both platforms run on the same 7.4V rail, share the same connector housing, and use the same BMS handshake protocol — a single cell SKU covers both.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Flyte platform, verified BMS communication at startup, and confirmed the charge IC accepted the cell without fault codes.
- Post-swap startup protocol: After installing this battery, let the Flyte complete its full power-on self-test sequence without removing or reinserting the cell. The BMS runs a chemistry verification check at boot — interrupting it before completion triggers a persistent battery fault that won't clear until the next clean reboot cycle.
Stryker Flyte showing low-battery alarm immediately after a confirmed full charge
The Flyte's BMS compares charge state against a stored OEM chemistry baseline. A new replacement cell that hasn't completed a full charge-discharge cycle reads slightly outside those calibrated thresholds, so the device flags it as low even when the cell is at full capacity. This is a BMS calibration issue, not a cell fault. Run one complete charge-discharge-recharge cycle before clinical use — after that cycle, the BMS recalibrates its threshold against the actual cell chemistry and the alarm clears.
Flyte headlight cutting out mid-procedure after the battery sat unused in storage
Li-ion cells self-discharge at roughly 1–3% per month in storage. If the cell drops below the BMS recovery threshold — typically around 2.5V per cell, or 5.0V across a 2S pack — the protection circuit locks the output and the device won't power on or stay on. Connect the battery to its charger and leave it for a full charge cycle without interruption. If the charger shows an active charge state within five minutes, the cell is recovering. If there is no charge current after ten minutes, check cell voltage directly — below 5.0V for the 2S pack indicates deep discharge requiring a trickle-recovery charger before normal charging resumes.