HTC Vive Focus B2PXH100 Replacement Battery 3.85V 3150mAh

HTC Vive Focus — 3.85V Li-Polymer Replacement Battery (B2PXH100)

This is a 3.85V 3150mAh Li-Polymer battery for the HTC Vive Focus standalone VR headset. It replaces part number B2PXH100 and powers the headset's display, processor, and inside-out tracking systems. Capacity is 3150mAh (12.13Wh), matching the original specification.

• Vive Focus compatibility: The Vive Focus uses a single internal battery cell at 3.85V nominal to run the Snapdragon 835 processor, LCD panel, and six-camera tracking array simultaneously. All three subsystems share this voltage rail, so the cell must hold its nominal voltage under combined load.
• Bench tested on actual hardware: We ran this cell in a Vive Focus unit under full tracking and rendering load. The BMS held charge distribution steady across draw spikes and engaged protection cutoff correctly at the low-voltage threshold without false trips.
• Pre-session charging for VR tracking stability: Always bring this battery to full charge before a long session. The Vive Focus tracking processors draw stable current even when the display dims — a partially charged cell can sag below the voltage floor the tracking subsystem needs, causing drift events mid-session.

Why the Vive Focus loses tracking when the battery drops below 20%

The six-camera inside-out tracking system on the Vive Focus requires a consistent voltage supply to process spatial data at the correct frame rate. As a Li-Polymer cell ages or discharges toward its lower limit, internal resistance rises and voltage sags under the combined GPU and camera-array draw. The tracking processor interprets this as a data timing error and resets its positional reference, which users see as a sudden jump or drift in the virtual environment. Keeping the cell above 20% — roughly 3.6V under load — prevents the tracking subsystem from hitting its floor.

Headset shuts down without warning mid-session

Unannounced shutdowns on the Vive Focus are almost always a voltage cliff event rather than a software crash. When a degraded or deeply discharged cell cannot sustain voltage under the simultaneous draw of the display, Snapdragon processor, and wireless stack, the BMS triggers an emergency cutoff to protect the cell — this happens in milliseconds with no gradual warning. A new cell with healthy capacity eliminates the internal resistance spike that causes the cliff. After fitting the replacement, power the headset on tethered to USB-C until the indicator shows full charge before running a standalone session.