I-Mate Smartflip STAR160 Replacement Battery 3.7V 850mAh

I-Mate Smartflip — 3.7V Li-ion Replacement Battery (STAR160)

This is a 3.7V, 850mAh Li-ion replacement battery for the I-Mate Smartflip flip phone. Part number STAR160 matches the original cell specification. Install it when the original battery no longer holds a charge or the phone shuts down unexpectedly under load.

• Smartflip fit: The Smartflip uses a compact flip-phone chassis with tight internal clearance. This cell matches the original 44.97 × 37.16 × 5.44mm footprint and the 3.7V nominal voltage rail the phone's charge IC expects. A mismatched cell thickness will prevent the back cover from seating correctly.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Smartflip platform and confirmed the BMS handshake completed without fault flags. The charge IC accepted the cell and terminated charging at the correct cutoff voltage without false-full events.
• First-cycle fuel gauge reset: After installation, run one full discharge down to auto-shutdown, then charge uninterrupted to 100%. This gives the phone's fuel gauge IC a complete discharge curve to reference against the new cell — without it, the coulomb counter carries over calibration data from the old degraded cell.

Sudden shutdown at 20–30% on the I-Mate Smartflip after a cell swap

This happens when the new cell hits a voltage cliff under modem or display load before the fuel gauge IC has mapped its actual discharge curve. The Smartflip's gauge still uses the old cell's internal resistance profile, so it reads 25% while the real cell voltage has already dropped below the BMS cutoff threshold. The phone cuts power to protect the cell before the OS can log a low-battery warning. One full uninterrupted discharge-to-shutdown cycle followed by a complete charge recalibrates the coulomb counter against the new cell.

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

Li-ion cells self-discharge in storage. If the STAR160 cell dropped below approximately 2.5V per cell, the BMS will lock out to prevent damage — the phone will show nothing when you press the power button. Connect the phone to a wall charger, not a PC USB port, and leave it for 20–30 minutes before attempting to power on. A PC port may not supply enough current to push the BMS out of lockout. Once the cell recovers above the BMS re-enable threshold, the phone will boot normally.