BTR5600B Qtek 8010 Replacement Battery 3.7V 2200mAh

Qtek 8010 — 3.7V Li-ion Replacement Battery (BTR5600B)

This is a 3.7V, 2200mAh Li-ion battery for the Qtek 8010 smartphone. It replaces OEM part numbers BTR5600B, ST26A, and ST26B. If your original cell has lost capacity or fails to hold charge through a normal day, this swap restores full functionality.

• Qtek 8010 compatibility: The 8010 uses a fixed 3.7V single-cell architecture. All three OEM references — BTR5600B, ST26A, ST26B — share the same voltage rail and connector footprint, so this cell covers all variants without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the bench. The BMS accepted charging from zero without tripping overcurrent protection, and voltage held stable above 3.6V through the bulk of the discharge curve.
• Fuel gauge recalibration after install: On first use, disable fast charging if available, then run one full discharge-charge cycle from 100% to shutdown and back. This lets the fuel gauge IC map the new cell's discharge curve before reporting percentage — skipping this step is the main reason users see erratic percentage jumps after a swap.

Sudden shutdown at 20–30% on the Qtek 8010 after a cell swap

The 8010's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage drop profile of the replacement. The phone's modem and screen draw spikes cause the voltage to sag below the shutdown threshold earlier than the percentage readout predicts. One full discharge-charge cycle forces the IC to relearn the curve against the new cell, and the premature cutoffs stop.

Qtek 8010 not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage. If this battery dropped below approximately 2.5V per cell before installation, the BMS enters a lockout state to prevent damage and the phone will not power on. Connect the phone to a charger and leave it for 15–20 minutes without pressing the power button — the charge IC needs to push a trickle current to bring the cell back above the BMS re-enable threshold of around 2.7V before a normal charge cycle can begin.