Emporia AK-V28 Replacement Battery 3.7V 1200mAh Li-ion

Emporia AK-V28 / AK-V29 — 3.7V Li-ion Replacement Battery (AK-V28-BC)

This is a 3.7V, 1200mAh Li-ion battery for the Emporia AK-V28, AK-V29, Talk Plus, and Talk Premium handsets. It replaces OEM part numbers AK-V28-BC and AK-V29-BC. Swap it in when the original cell no longer holds charge or the phone shuts down before reaching zero percent.

• AK-V28 and AK-V29 platform fit: Both handsets share the same PCB layout, connector pinout, and BMS handshake protocol — one cell covers all listed models without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the AK-V28 chassis. The BMS accepted the charge profile without triggering overcurrent cutoff, and voltage held within spec at the 3.7V nominal rail throughout.
• Fuel gauge recalibration after install: On first use, let the phone discharge to auto-shutdown, then charge uninterrupted to 100% before use. This gives the fuel gauge IC one complete reference cycle against the new cell's actual discharge curve — skip it and the percentage readout will drift.

Sudden shutdown at 20–30% on the Emporia AK-V28

The AK-V28 fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell has a slightly different voltage-to-capacity slope, so the IC miscalculates remaining charge. When the modem fires during a call or the screen backlight peaks, current draw spikes and actual cell voltage drops below the BMS cutoff threshold — even though the display showed 25%. One full discharge-charge cycle after installation resets the coulomb counter and corrects this behaviour.

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

Li-ion cells self-discharge during storage. If the cell drops below approximately 2.5V, the BMS enters a lockout state to prevent further discharge damage. The phone will not respond to the power button and may show nothing on screen. Connect the phone to a wall charger — not a PC USB port — and leave it for 15–20 minutes without pressing anything. The charge IC will trickle current into the cell until voltage climbs above the BMS re-enable threshold, typically around 2.9V, at which point normal charging resumes.