Motorola ET1 Tablet Replacement Battery 3.7V 4500mAh

Motorola ET1 — 3.7V Li-ion Replacement Battery (82-149690-01)

This is a 3.7V, 4500mAh Li-ion battery for the Motorola ET1 enterprise tablet. It replaces OEM part numbers 82-149690-01 and BTRY-ET01EAB0E. If your ET1 is shutting down early, failing to hold charge, or not powering on, this battery addresses cell-level degradation in the original unit.

• ET1 tablet platform: The ET1 uses a single-cell Li-ion pack with a BMS that communicates state-of-charge data to the Android OS fuel gauge IC. Voltage, connector pinout, and BMS handshake must match exactly — this cell meets all three.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on the ET1 platform. The BMS reported cell status correctly to the host OS, and the charge IC accepted the full 4500mAh capacity without cutoff errors.
• Fuel gauge recalibration after swap: After installing this battery, run the ET1 down to automatic shutoff, then charge it uninterrupted to 100%. This forces the fuel gauge IC to recalibrate against the new cell and corrects the percentage drift that almost always appears after a battery swap.

ET1 shutting down at 15–25% battery remaining

The ET1's display backlight and WiFi radio together create a combined load spike that the fuel gauge IC reads against the old cell's discharge curve. When a new cell is installed without recalibration, the IC still predicts voltage collapse earlier than it actually occurs. The tablet interprets this as a critically low battery and shuts down — even though real capacity remains. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% rewrites the calibration baseline and eliminates the early cutoff.

ET1 showing wrong battery percentage after replacement

The fuel gauge IC in the ET1 builds its charge model from historical discharge data tied to the old cell's internal resistance profile. A new cell has a lower internal resistance, so the IC's learned curve no longer matches actual voltage behaviour — it reports figures that are consistently off by 10–20%. This isn't a fault with the replacement battery. Run one complete cycle: discharge to automatic shutoff, then charge to 100% without interruption. The IC resets its model at 4.2V termination and percentage accuracy returns to normal.