KNmobile Nokia N4 I736 Replacement Battery 3.7V 1500mAh

KNmobile Nokia N4 (I736) — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1500mAh Li-ion battery for the Nokia N4 smartphone, model I736. It replaces the original cell when the phone no longer holds a charge or shuts down unexpectedly. Dimensions are 65.80 × 43.90 × 5.10mm — confirm against your existing cell before installing.

• Nokia N4 I736 fit: The I736 uses a fixed voltage rail at 3.7V nominal with a specific connector orientation and BMS handshake tied to this cell footprint. Swapping to a different cell profile breaks that handshake and can prevent the phone from powering on at all.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an I736 unit. The BMS accepted the cell without fault codes, charge termination triggered correctly at 4.2V, and the fuel gauge IC began tracking state-of-charge within one full cycle.
• First-cycle calibration tip: On first use after installation, disable fast charging if the phone supports it. Run one complete discharge-to-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — otherwise percentage readings will drift.

Why the Nokia N4 reports wrong battery percentage after a cell swap

The I736's fuel gauge IC stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry and capacity. The phone reads voltage and maps it to a percentage using the old data — so it can show 40% when the cell is closer to 15%. One full discharge-charge cycle at standard current forces the IC to re-learn the curve and bring percentage reporting back into alignment.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity defect. Under heavy load — modem activity, screen at full brightness, active apps — the cell voltage drops faster than the fuel gauge IC predicts. When voltage hits the BMS cutoff threshold (typically around 3.0–3.2V under load), the phone shuts down even though the displayed percentage looks safe. The fix is to let the fuel gauge complete two or three full cycles so it can account for the cell's internal resistance under real load conditions. After recalibration, shutdowns at 20–30% should stop.