HTC Tanager PC26A Replacement Battery 3.7V 1150mAh

HTC Tanager — 3.7V Li-ion Replacement Battery (PC26A)

This is a 3.7V, 1150mAh Li-ion replacement battery for the HTC Tanager smartphone. It fits directly in place of the original PC26A cell. Voltage and capacity match the stock specification exactly.

• HTC Tanager fit: The Tanager uses a single-cell 3.7V nominal architecture with a proprietary connector keyed to the PC26A form factor. The BMS handshake is voltage-threshold based — no authentication chip — so the replacement cell communicates with the charge IC the same way the original does.
• Bench tested on actual hardware: We ran the PC26A replacement through charge and discharge cycles on the Tanager platform. The charge IC accepted the cell without fault codes, and the BMS cutoff triggered correctly at both ends of the voltage window.
• Fuel gauge recalibration on first cycle: After installing this cell, run one full discharge to automatic shutdown followed by an uninterrupted charge to 100% before normal use. The Tanager's fuel gauge IC was calibrated to the old cell's discharge curve — skipping this step causes the percentage counter to read inaccurately for the first several cycles.

Why the Tanager reports wrong battery percentage after a cell swap

The Tanager uses a coulomb-counting fuel gauge IC that builds its percentage model from accumulated charge and discharge data on the original cell. When you install a new cell, that learned model no longer matches the actual discharge curve of the replacement. The IC continues reporting against the old curve until it can measure a full cycle on the new cell. One complete discharge-to-shutdown followed by a full charge resets the baseline and brings the percentage readout back into alignment.

Sudden shutdown at 20–25% on the replacement cell

This happens when the modem or display draws a high current pulse and the cell voltage drops below the BMS cutoff threshold faster than the fuel gauge tracks it. On a freshly installed cell, internal impedance is slightly higher than a broken-in cell, which steepens the voltage sag under load. The BMS sees the rail drop below 3.0V and cuts power before the percentage counter reaches zero. Running two or three full discharge-charge cycles lowers effective impedance and flattens the sag curve — most users stop seeing the shutdown below 15% after cycle three.