NEC Terrain NE-201A1B Replacement Battery 3.7V 1400mAh

NEC Terrain / NE-201A1A — 3.7V Li-ion Replacement Battery (NE-201A1B)

This is a 3.7V, 1400mAh Li-ion replacement battery for the NEC Terrain smartphone (model NE-201A1A). It uses OEM part number NE-201A1B and slots directly into the existing battery bay. Capacity is 1400mAh — matching the original cell specification.

• Terrain and NE-201A1A compatibility: Both the Terrain and NE-201A1A share the same battery bay dimensions, connector pinout, and charge IC protocol. The BMS on this cell communicates with the same fuel gauge IC used across both variants, so the OS reads charge state correctly from the first boot.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Terrain platform. The BMS held stable cutoff at 4.2V charge and 3.0V discharge floor, with no spurious low-battery shutdowns during high-load screen and modem activity.
• Fuel gauge recalibration on first install: After fitting this cell, run one full discharge to automatic shutdown followed by an uninterrupted charge to 100% before enabling fast charging — this gives the coulomb counter in the fuel gauge IC a clean baseline discharge curve to reference. Skipping this step causes erratic percentage reporting for the first several cycles.

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

This is a voltage cliff problem, not a capacity fault. The Terrain's modem and display draw a combined current spike that a new, uncalibrated cell struggles to sustain at mid-state-of-charge. The fuel gauge IC still shows 20–30% remaining, but the cell voltage collapses under load below the BMS cutoff threshold and the phone cuts power instantly. One full discharge-charge cycle recalibrates the fuel gauge against the actual cell discharge curve, and the shutdowns stop.

Phone won't power on after the battery sat discharged in storage

Li-ion cells self-discharge in storage. If the Terrain sat unused for several months with this battery installed and below the 2.5V-per-cell floor, the BMS enters lockout mode to prevent cell damage and blocks normal boot. Plugging in a charger and seeing no response or a flashing LED is the tell. Connect to a wall charger — not a PC USB port — and leave it for 20–30 minutes without pressing any buttons. The charge IC will trickle current into the cell until voltage rises above the BMS re-enable threshold, typically around 2.9V, at which point the phone will begin a normal charge cycle.