Samson Airline 88 Fitness Replacement Battery 3.7V 500mAh

Samson Airline 88 / 99 Fitness — 3.7V Li-Polymer Replacement Battery (1ICP7/21/41)

This 3.7V, 500mAh Li-Polymer cell is a direct replacement for the internal battery in the Samson Airline 88 Fitness and Airline 99 Fitness wireless headsets. It fits the compact 41.80 × 19.50 × 6.00mm battery bay inside the headset body. Replace this cell when the original no longer holds adequate charge for your sessions.

• Airline 88 and 99 Fitness compatibility: Both models run the same 3.7V power rail, share the same battery bay dimensions, and use the same BMS handshake with the transmitter circuit — one cell covers both.
• Bench tested on actual hardware: We ran this cell through full charge-discharge cycles on the Airline 88 Fitness transmitter board. The BMS accepted the new pack without fault codes, and the DECT radio and microphone draw remained stable across the test window.
• First-cycle charging on the Airline headset: After fitting, seat the headset in its base station and let it complete one uninterrupted full charge before use. The base station needs that full cycle to log the new cell and calibrate the charge-state indicator — skip it and the battery meter will read inaccurately from the start.

Why the Airline 88 Fitness cuts out mid-workout on a new battery

The Airline 88 Fitness combines a DECT radio transmitter and a condenser microphone in a very small housing. Under peak combined draw — radio burst plus mic preamp — the BMS can trip a temporary cutoff if the cell voltage sags below its protection threshold. A brand-new Li-Polymer cell at storage charge (around 3.6–3.7V) is more prone to this than a fully conditioned cell. Charge fully before first use and run three to five full cycles to let the cell reach its rated capacity headroom.

Base station shows full charge but headset dies quickly after replacing the battery

This happens when the base station reads the new cell's resting voltage as "full" without completing an actual charge cycle — common with Li-Polymer cells shipped at storage voltage. The indicator reflects voltage, not true state of charge. Seat the headset in the base, leave it for a complete uninterrupted charge cycle, then test again. After that first full cycle the talk-time will reflect the actual 500mAh capacity of the new cell.