About this replacement
HTC Andes — 3.7V Li-Polymer Replacement Battery (BP-XDA2-12)
This 3.7V, 1400mAh Li-Polymer cell is a direct replacement for the HTC Andes smartphone. It fits the Andes specifically — voltage and connector match the original HTC spec. Capacity is 1400mAh (5.18Wh), drawn from product data, not estimated.
- HTC Andes fit: The Andes uses a fixed 3.7V Li-Polymer cell with a proprietary connector and a fuel gauge IC that tracks coulombs against the original cell's discharge curve. This replacement cell matches voltage, capacity rating, and connector pinout so the phone's power management IC does not flag a hardware mismatch on boot.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Andes platform. The BMS accepted the cell without lockout, and charge termination triggered at the correct cutoff voltage with no thermal event during the charge phase.
- Fuel gauge recalibration on first use: On first installation, disable any fast-charge mode and run one full discharge-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before it locks in percentage readings — skipping this step is the main reason users see erratic percentage jumps after a cell swap.
Why the Andes reports wrong battery percentage after a cell swap
The Andes uses a coulomb-counting fuel gauge IC that stores a learned discharge model of the original cell. When a new cell goes in, that stored model no longer matches the new cell's actual voltage-to-capacity curve. The IC keeps reporting percentage against the old model until it recalibrates. One full discharge to near shutdown followed by a complete charge cycle resets the learned curve and brings percentage reporting back into accurate range.
Sudden shutdown at 20–30% on the replacement cell
This happens when the fuel gauge IC has not yet recalibrated and the cell hits a voltage cliff under load — typically when the modem or display draws a current spike. The cell voltage drops below the protection threshold faster than the reported percentage suggests, and the BMS cuts power. It is not a faulty cell. Run one full discharge-charge cycle to let the IC recalibrate, then confirm the cell holds above 3.5V under screen-on load before calling it a hardware fault.