AB603443EZ Verizon SCH-U940 Replacement Battery 3.7V 1000mAh

Verizon SCH-U940 Glyde — 3.7V Li-ion Replacement Battery (AB603443EZ)

This is a 3.7V, 1000mAh Li-ion battery for the Verizon SCH-U940, also sold as the U940 Glyde and SCH-U940v. It replaces OEM part AB603443EZ in the original flip-style touchscreen handset. Capacity is 3.7Wh — matching the factory spec for this device.

• SCH-U940, U940 Glyde, SCH-U940v compatibility: All three model designations refer to the same Samsung-built Verizon handset. The connector pinout, cell footprint, and BMS handshake are identical across the variant codes, so one cell fits all three.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence on the SCH-U940 platform. The BMS accepted the charge current without fault flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: Disable any fast-charge accessories for the first complete discharge-charge cycle after fitting this cell. The fuel gauge IC on the U940 calibrates its discharge curve on that first full cycle — running it uncalibrated under high current produces erratic percentage readings from the second charge onward.

Why the U940 Glyde reports wrong battery percentage after a cell swap

The SCH-U940 uses a fuel gauge IC that tracks capacity by measuring coulombs against a stored discharge curve. That curve was mapped to the original cell's impedance profile. A new cell has different internal resistance, so the IC's state-of-charge estimate drifts against the actual cell voltage. The fix is one complete discharge down to auto-shutoff, followed by a full uninterrupted charge. After that cycle, the IC resets its reference points against the new cell and percentage readings stabilise.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage collapses faster than the fuel gauge predicts under load — typically when the display backlight and radio fire simultaneously. The IC still shows 25% remaining, but the cell is already near 3.4V under draw and drops below the BMS cutoff threshold. On the U940, this is most visible during calls with max backlight active. Run one full calibration cycle first; if shutdowns persist, check that resting open-circuit voltage sits at or above 3.7V after a full charge.