AudioVox SMT5600 Replacement Battery 3.7V 2200mAh

AudioVox SMT5600 — 3.7V Li-ion 2200mAh Replacement Battery

This is a 3.7V lithium-ion battery rated at 2200mAh (8.14Wh) for the AudioVox SMT5600 smartphone. It replaces the original cell when the phone no longer holds charge through a normal day of calls, messaging, and app use. Swap it in when the original cell has degraded past useful capacity.

• SMT5600 fitment: The SMT5600 uses a single 3.7V Li-ion cell in a standard removable form factor. This battery matches the voltage rail and contact layout the phone's charge IC expects. No adapter or modification required.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the SMT5600 platform. The BMS handshake completed normally on first connection — the charge IC accepted the cell and initiated charge current without fault flags.
• Fuel gauge recalibration on first use: On first installation, disable fast charging if the option is available and run one complete discharge-charge cycle before normal use. This lets the fuel gauge IC map the new cell's discharge curve before it commits to a percentage reading.

Why the SMT5600 reports wrong battery percentage after a cell swap

The SMT5600 uses a fuel gauge IC that tracks charge state against a learned discharge curve from the previous cell. When you install a new cell, the IC still references that old curve. The result is percentage readings that don't match actual charge state — it may show 80% and drop to zero within minutes. One full discharge-to-shutdown followed by an uninterrupted charge to 100% forces the IC to recalibrate against the new cell. After that cycle, percentage accuracy returns to normal.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below what the modem or screen load requires, even though the fuel gauge still shows charge remaining. The original cell had a gradual voltage sag curve the IC knew; a new cell has a slightly different one. Under a high-draw moment — an incoming call, screen wake, or data sync — the voltage dips past the shutdown threshold before the gauge reads zero. Run two full discharge-charge cycles to let the coulomb counter recalibrate, then check if shutdowns persist. If they stop after recalibration, the gauge was the cause. If they continue, check that the battery contacts are clean and seating at full depth — target a resting voltage of 3.7V measured at the contacts before power-on.