HyperX Cloud III Wireless Compatible Battery 3.7V 1200mAh

HyperX Cloud III Wireless-Gaming Headset — 3.7V Li-Polymer Replacement Battery (AHB603450)

This 3.7V, 1200mAh Li-Polymer cell replaces the original AHB603450 battery in the HyperX Cloud III Wireless-Gaming Headset. It restores cordless audio and wireless functionality when the factory cell has degraded or failed. Dimensions are 51.00 x 33.80 x 6.30mm — a direct physical match for the Cloud III housing.

• Cloud III Wireless compatibility: The Cloud III Wireless runs a combined audio DSP and 2.4GHz radio load from a single cell. This replacement matches the original voltage rail and connector orientation so the headset's onboard BMS accepts the new pack without a firmware conflict.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Cloud III platform. The BMS handshake completed cleanly, charge acceptance was normal, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• First-cycle charge protocol for the Cloud III: Place the headset in its USB-C charging dock and run a full uninterrupted charge before first use. The Cloud III's firmware calibrates its talk-time estimate against the new cell's first complete charge curve — skipping this step causes the battery indicator to report inaccurate levels for the first several sessions.

Why the Cloud III Wireless cuts out mid-session under combined audio and radio draw

The Cloud III pulls current from two sources simultaneously — the 2.4GHz transceiver and the audio processing circuit. A degraded or partially charged cell can't sustain that combined draw without voltage sagging below the BMS cutoff threshold, which the headset reads as a dead battery. This trips an automatic shutdown even when the indicator shows charge remaining. A fresh cell at full capacity handles the peak draw without the sag that triggers the cutoff. If dropouts continue after a full first cycle, check that the USB-C dock is delivering consistent current — a marginal cable causes incomplete charges that mimic a failing cell.

Base station shows charging error after fitting the new cell

This happens when the BMS hasn't completed its initial handshake with the charging circuit. The dock reads the pack as unrecognised and flags an error rather than beginning the charge cycle. Remove the headset from the dock, hold the power button for 10 seconds to fully discharge any residual capacitor voltage, then reseat it in the dock. The BMS re-initialises on the next connection attempt and the charging indicator should switch to a normal charge state within 60 seconds.