AT&T Vivid 4G Replacement Battery 3.7V 1400mAh

AT&T Vivid 4G — 3.7V Li-ion 1400mAh Replacement Battery

This is a 3.7V, 1400mAh Li-ion replacement battery for the AT&T HTC Vivid 4G Android smartphone. It fits the Vivid 4G directly and matches the original cell's voltage and physical dimensions. Capacity is 1400mAh (5.18Wh) — taken from product data, not estimated.

• Vivid 4G fit: The Vivid 4G uses a removable battery with a specific contact layout and 54.90 x 47.92 x 5.20mm footprint. This cell matches that footprint and connector orientation. No adapter or modification needed.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Vivid 4G unit. The BMS accepted the charge handshake without fault flags. Voltage held stable across screen-on and LTE-active load states.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one full discharge-to-charge cycle before heavy use. The Vivid 4G's fuel gauge IC calibrated to the original cell's discharge curve — giving it one full uninterrupted cycle lets it remap to the new cell and report accurate percentages.

Sudden shutdown at 20–30% on the Vivid 4G after a cell swap

The Vivid 4G's Snapdragon S3 processor and LTE modem pull current in sharp spikes. A new cell with an uncalibrated fuel gauge IC causes the OS to misread state of charge. When the real cell voltage drops under load to around 3.5V, the phone shuts down even though the display showed 25% remaining. One full discharge cycle — draining to auto-shutdown and charging uninterrupted to 100% — gives the coulomb counter enough data to correct this.

Phone shows wrong battery percentage after replacement

The fuel gauge IC on the Vivid 4G stores a learned discharge curve from the old cell. When a new cell goes in, those stored values no longer match actual cell chemistry, so the percentage reading drifts or jumps. The fix is a full recalibration cycle: charge to 100%, use the phone until it shuts off on its own, then charge back to 100% in one session without interruption. After that cycle, percentage readings stabilise at the correct values.