Tecno HD61 Album 3.7V Replacement Battery 750mAh Li-ion

Tecno HD61 Album — 3.7V Li-ion Replacement Battery

This is a 3.7V, 750mAh Li-ion replacement cell for the Tecno HD61 Album mobile phone. It slots directly into the HD61 Album battery bay and restores power when the original cell can no longer hold charge. Dimensions are 53.00 × 33.90 × 5.70mm — confirm these against your existing battery before fitting.

• HD61 Album platform fit: The HD61 Album runs a low-voltage 3.7V power rail matched to a slim chassis. This cell meets that voltage spec and physical envelope. No BMS protocol mismatch was found during testing on this platform.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the HD61 Album. The onboard charge IC accepted the cell without fault flags, and the BMS reached cutoff at the expected terminal voltage without interruption.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Why the HD61 Album reports wrong battery percentage after a cell swap

The HD61 Album uses a fuel gauge IC that tracks charge by measuring cumulative current flow — a coulomb counter approach. When the original cell ages, the phone recalibrates its empty and full thresholds to match that degraded cell's curve. A new cell has a different discharge profile, so the IC's stored calibration no longer maps accurately to real charge state. One full discharge-to-shutdown followed by an uninterrupted charge to 100% resets the calibration and brings percentage readings back in line.

Sudden shutdown at 20–30% on the new cell

This happens when the fuel gauge IC still holds the old cell's voltage curve and calls shutdown too early. Under modem or screen load, voltage sags briefly — and if the IC's low-voltage threshold is mapped to a worn cell, it triggers cutoff before the new cell is actually empty. The fix is a full recalibration cycle: drain the phone until it shuts itself off, then charge uninterrupted to 100% without removing the charger. After one complete cycle, the IC updates its floor voltage reference and the early shutdowns stop.