KONKA W991 Replacement Battery KLB200N289 3.7V 2000mAh

KONKA W991 — 3.7V Li-ion Replacement Battery (KLB200N289)

This is a 3.7V, 2000mAh Li-ion cell built to the KLB200N289 specification for the KONKA W991 smartphone. It replaces the original battery when capacity fade makes the phone unreliable through a full day of use. Dimensions are 70.18 × 60.00 × 4.67mm — confirm these against your existing cell before installation.

• W991 fitment: The W991 uses a fixed voltage rail at 3.7V nominal with a connector and cell footprint specific to this candybar form factor. Any cell substitution outside the KLB200N289 footprint will not seat correctly against the board connector.
• Bench tested on actual hardware: We cycled this cell through charge, load, and BMS cutoff checks. The protection circuit responds correctly to over-current and reaches full charge termination without false cutoff at the top of the curve.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC learn the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the W991 after a cell swap

This is a voltage cliff issue, not a capacity problem. The W991's modem and display draw a combined current spike that the new cell cannot sustain if the fuel gauge IC is still calibrated to the old degraded cell's curve. The phone's OS believes 25% remains, but the actual cell voltage collapses under load and the protection circuit cuts power. Run one full discharge down to automatic shutdown, then charge uninterrupted to 100% — after that cycle the fuel gauge recalibrates and the shutdowns stop.

W991 not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage and can drop below 2.5V per cell — at that point the BMS locks out to prevent damage and the phone will not respond to a normal power-on attempt. Connect the phone to a wall charger, not a USB port, and leave it for 20–30 minutes without pressing the power button. The charge IC applies a low-current pre-charge trickle that recovers the cell voltage above the BMS re-enable threshold. Once the screen shows a charging indicator, the BMS has re-initialised and normal charging resumes.