Uniscope U73 Replacement Battery 3.7V 1000mAh Li-ion

Uniscope U73 — 3.7V Li-ion 1000mAh Replacement Battery

This is a 3.7V Li-ion cell rated at 1000mAh (3.7Wh), built to fit the Uniscope U73 smartphone. It replaces the original cell when the factory battery no longer holds a charge through normal daily use. Dimensions are 53.00 × 33.90 × 5.70mm — verify these against your existing cell before installing.

• U73 fit: The U73 uses a compact removable cell on a 3.7V single-cell Li-ion voltage rail. This replacement matches that rail, the physical footprint, and the connector orientation so the battery seats correctly in the chassis.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench, confirmed the BMS accepted a full charge without tripping, and checked that charge termination cut off cleanly at 4.2V.
• First-cycle fast charge tip: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the U73's fuel gauge IC recalibrate its discharge curve against the new cell before high-current charging runs against an uncalibrated register.

Sudden shutdown at 20–30% on the U73 after a cell swap

After replacing the cell, the U73 may shut down abruptly while the OS still shows 20–30% remaining. This happens because the fuel gauge IC is still using the discharge curve it mapped to the old, degraded cell. When modem transmit bursts or screen load spike current draw, the new cell's actual voltage drops below the shutdown threshold faster than the stale curve predicts. Run two full discharge-charge cycles without fast charging and the gauge will remap to the new cell's actual capacity curve.

U73 not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage, and if voltage drops below approximately 2.5V per cell the BMS trips into deep-discharge lockout to protect the cell. The U73 will show no sign of life — no boot screen, no charge indicator. Connect the phone to a 5V USB charger and leave it undisturbed for 15–30 minutes. The charge IC will trickle current into the cell until voltage recovers above the BMS re-enable threshold, typically around 2.9V, after which normal charging resumes.