AT&T Maestro LT20H445170B Replacement Battery 3.8V 1950mAh

AT&T Maestro / U202AA — 3.8V Li-ion Replacement Battery (LT20H445170B)

This is a 3.8V, 1950mAh Li-ion replacement battery for the AT&T Maestro (U202AA) smartphone. It replaces OEM part numbers LT20H445170B and LT20H445170W. If your Maestro is shutting down unexpectedly, not holding a charge, or won't power on at all, this cell is the direct swap.

• Maestro / U202AA fit: Both the Maestro and U202AA designations refer to the same hardware platform and share an identical battery connector, voltage rail, and BMS handshake. One cell covers both variants without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Maestro platform. The BMS accepted the cell on first connection, charge termination triggered correctly at 4.35V, and low-voltage cutoff engaged as expected without requiring a reset.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC pushes higher current into an uncalibrated cell.

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

This is a voltage cliff issue, not a capacity problem. Under modem or display load, the new cell briefly sags below the shutdown threshold even though the fuel gauge still reads 20–30%. The fuel gauge IC hasn't yet mapped the new cell's discharge curve, so it misjudges the remaining usable voltage. One full discharge-charge cycle at standard rate gives the coulomb counter enough data to correct its estimate and the shutdowns stop.

Device not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage, and if the cell dropped below 2.5V the BMS enters a lockout state to prevent damage. The phone will show no response — no charging indicator, no boot. Connect to a wall charger rated at least 5V/1A and leave it for 20–30 minutes without pressing the power button. The charge IC will trickle current into the cell until voltage recovers above the BMS re-enable threshold, after which normal charging resumes.