Corsair HS75 XB Replacement Battery 3.7V 1200mAh

Corsair HS75 XB / Void Pro RGB Series — 3.7V Li-Polymer Replacement Battery (AEC524050)

This is a 3.7V, 1200mAh Li-Polymer replacement cell for the Corsair HS75 XB, HS70 SE, Void Pro RGB, and HS70SE wireless headsets. It replaces the original AEC524050 pack that degrades after repeated charge cycles. Voltage and physical dimensions match the factory cell exactly: 52.80 × 39.80 × 5.00mm.

• HS75 XB and Void Pro RGB platform fit: These models share the same 3.7V power rail, connector pinout, and internal BMS handshake protocol. One cell fits all four headset variants listed because the audio DSP and 2.4GHz radio module run off the same regulated supply.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the HS75 XB base station. The BMS accepted the pack without error flags, balanced charge terminated cleanly at 4.2V, and the headset reported a full charge state to the base unit.
• First charge on the Corsair base station: Seat the headset in the base and leave it undisturbed through one complete charge cycle before use. The base station logs the new cell's capacity during that first cycle — skipping it causes the talk-time indicator to read inaccurately for several sessions.

Why the HS75 XB cuts out mid-session on a new battery

The HS75 XB draws from two loads simultaneously — the audio DSP and the 2.4GHz radio. Under combined draw, a cell sitting at storage voltage (around 3.6–3.7V) can sag below the BMS cutoff threshold even when the base showed a full charge. This is not a faulty cell. It happens because the pack arrived at partial state of charge and was never conditioned through a full cycle. One full charge on the base station before the first extended session resolves it. After two to three full cycles, sag under combined load drops noticeably.

Base station showing a charging error after fitting the new pack

The Corsair base performs a BMS handshake when a headset is docked — it reads cell voltage before enabling the charge circuit. If the replacement cell arrives below 3.5V, the base may flag a charge fault rather than begin charging. Remove the headset, wait 10 seconds, and re-dock it firmly. If the error persists, the cell voltage may need a brief recovery charge — some base stations require the cell to be above 3.4V to initiate. Confirm the dock contacts are clean and fully seated before assuming the cell is at fault.