AT&T 575 Replacement Battery 3.7V 980mAh Li-ion

AT&T 575 — 3.7V Li-ion Replacement Battery

This is a 3.7V Li-ion cell rated at 980mAh (3.63Wh), built to fit the AT&T 575 smartphone. It replaces the original cell when capacity has dropped to the point where the phone no longer holds a usable charge. Dimensions are 70.40 x 46.80 x 5.40mm — verify these against your existing cell before ordering.

• AT&T 575 fit: The 575 uses a fixed connector pinout tied to this specific cell footprint. Voltage rail and physical dimensions must match exactly — this cell meets both requirements for the 575 platform.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge passes, confirming the BMS holds the 4.2V upper cutoff and trips correctly at the low-voltage floor without false shutdowns mid-cycle.
• Fuel gauge recalibration on first use: On first installation, run one complete discharge to shutdown followed by a full uninterrupted charge. This gives the phone's fuel gauge IC a clean reference curve against the new cell before it starts reporting percentage data to the OS.

Sudden shutdown at 20–30% on the AT&T 575 after a cell swap

The AT&T 575 reads remaining charge through a fuel gauge IC that was calibrated to the original cell's discharge curve. A new cell has a different internal resistance profile, so the IC misjudges how much voltage is left under load. When the modem fires up for a call or the screen peaks in brightness, the new cell's voltage dips below what the IC expects at that charge level. The phone interprets this as a critical low-voltage event and shuts down — even though the cell still has charge. One full discharge-charge cycle recalibrates the coulomb counter and eliminates most of these early cutoffs.

Battery percentage jumping erratically after replacement

Erratic percentage jumps — say, 45% dropping to 12% in seconds — point to the fuel gauge IC working from stale calibration data stored during the life of the old cell. The IC uses a coulomb counter that tracks charge in and out, but the baseline it anchors to no longer matches the new cell's chemistry state. This is not a fault in the replacement cell. Charge the phone to 100%, let it discharge fully until it shuts itself off, then charge back to 100% without interruption — after that cycle, the reported percentage should stabilise.