Mobiado Classic 712 Stealth LE Replacement Battery 3.7V 800mAh

Mobiado Classic 712 Series — 3.7V Li-ion Replacement Battery

This is a 3.7V, 800mAh (2.96Wh) lithium-ion cell for the Mobiado Classic 712 Stealth LE, Classic 712EM, Classic 712GCB, and Classic 712ZAF. All four variants share the same battery bay dimensions and voltage rail. Swap it in when the original cell can no longer hold charge through a normal day of calls and messaging.

• Classic 712 variant compatibility: The Stealth LE, EM, GCB, and ZAF share identical battery dimensions (39.75 × 37.75 × 6.50mm), the same 3.7V nominal rail, and the same connector orientation. The BMS handshake is consistent across all four, so one cell covers the full lineup.
• Bench tested on actual hardware: We cycled this cell through charge and discharge under simulated call and standby loads. The BMS engaged protection cutoff correctly at both low-voltage and overcharge thresholds with no anomalies.
• Fuel gauge recalibration on first use: On first installation, disable fast charging if available and run one complete discharge-to-charge cycle. The fuel gauge IC on this phone is calibrated to the old cell's discharge curve. One full cycle lets it remap against the new cell before the OS starts reporting accurate percentages.

Sudden shutdown at 20–30% on the Classic 712 after a cell swap

This phone's power IC monitors cell voltage in real time. A fresh cell has a slightly different voltage-to-capacity curve than the aged original. When the fuel gauge IC hasn't recalibrated, it misreads remaining capacity and the phone hits the hardware low-voltage cutoff while the OS still shows charge remaining. The fix is one full discharge down to automatic shutdown, then a full uninterrupted charge to 100%. After that cycle, the gauge IC maps the new curve and the early shutdowns stop.

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

Li-ion cells self-discharge during storage. If this battery dropped below roughly 2.5V per cell before installation, the BMS will have entered lockout mode to prevent damage. The phone will show no response — no boot screen, no charge indicator. Connect it to a wall charger and leave it for 15–20 minutes before attempting to power on. Most BMS circuits will accept a trickle recovery current and release the lockout once the cell climbs back above the minimum threshold voltage.