About this replacement
Corsair HS70 / HS75 XB / VOID Series — 3.7V Li-Polymer Replacement Battery (AHB504258)
This is a 3.7V, 1400mAh Li-Polymer replacement battery for the Corsair HS70, HS70SE, HS75 XB, and VOID wireless headset series. It replaces OEM part number AHB504258. Fit this battery when the original cell no longer holds enough charge to sustain a full session.
- HS70, HS70SE, HS75 XB, and VOID compatibility: These models share the same 3.7V cell format, connector type, and BMS handshake protocol. Swapping this battery across any of them keeps the charge reporting accurate inside Corsair iCUE.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the HS70 platform. The BMS accepted the pack without error, charge indicators responded correctly, and iCUE reported battery state as expected throughout.
- First-cycle base station charge: Seat the headset in its base station and let it complete one full uninterrupted charge before use. The base needs to complete a full charge handshake with the new cell before the talk-time estimate in iCUE reads accurately.
Why the HS70 cuts out mid-session even on a charged battery
The HS70 draws from two loads simultaneously — the DECT radio and the audio DSP. Under that combined draw, a degraded or freshly installed cell can sag below the BMS cutoff threshold before the reported percentage reaches zero. The headset drops audio or disconnects entirely, even though iCUE showed 20–30% remaining moments earlier. This is a voltage sag event, not a capacity fault. After the first three to five full cycles on a replacement cell, internal resistance drops and the sag narrows — the cutoff threshold sits around 3.0V on this platform.
Base station shows full charge but headset shuts off after a few minutes
A new Li-Polymer cell ships at storage voltage — roughly 3.6–3.8V — not at full charge. The base station can misread this as a complete charge and stop the charge cycle early. The headset then runs from a partially filled cell and cuts off quickly. Pull the headset from the base, power it on until it shuts down from low battery, then reseat it for a full uninterrupted charge. That forces the charger to re-evaluate the cell from a true low-state and fill it to the correct 4.2V endpoint.