KNmobile I736 Replacement Battery 3.7V 1700mAh Li-ion

KNmobile I736 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1700mAh (6.29Wh) lithium-ion cell from KNmobile's X-Longer series. It fits the Nokia N4 and replaces the original I736 battery. Use it when the original cell no longer holds a charge or the phone shuts down unexpectedly under load.

• Nokia N4 fit: The I736 form factor — 66.20 × 44.00 × 5.10mm — matches the Nokia N4 battery bay directly. The connector pinout and BMS handshake align with the N4's charge controller, so the phone recognises the cell and applies the correct charge curve.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the bench. The BMS responded correctly to charge termination, and the protection circuit tripped cleanly at the low-voltage cutoff threshold — no runaway or false shutdown above 3.0V.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the Nokia N4's fuel gauge IC map the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the Nokia N4 after a cell swap

This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. The new cell has a steeper voltage cliff at different state-of-charge points, so the IC miscalculates remaining capacity. When the modem fires or the screen peaks in brightness, the cell voltage drops briefly below the shutdown threshold — even though the reported percentage says 25%. One full discharge-to-charge cycle resets the coulomb counter and maps the correct voltage curve to the new cell.

OS reporting wrong battery percentage after replacement

The Nokia N4's fuel gauge IC retains the learned discharge profile from the previous cell. After swapping in a fresh 1700mAh cell, the percentage can jump erratically or read higher than actual. This is a calibration issue, not a fault with the replacement cell. Drain the battery until the phone shuts off automatically, then charge uninterrupted to 100% — after one full cycle the gauge IC recalibrates to the new cell and readings stabilise.