Beeline M2 Replacement Battery 3.7V 3400mAh Li-ion

Билайн M2 / V9+ — 3.7V Li-ion Replacement Battery

This 3.7V, 3400mAh Li-ion battery replaces the original cell in the Билайн M2 and V9+ tablets. Both models share the same voltage rail, physical footprint (127.70 × 60.13 × 4.67mm), and connector configuration. Capacity is rated at 12.58Wh, matching the original cell specification.

• M2 and V9+ shared platform: Both tablets run the same charge IC and BMS handshake protocol. The same connector pinout and voltage rail means one cell fits both without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the M2 platform. The BMS accepted the cell cleanly — no cutoff errors, no charge-fault flags during the full cycle.
• Post-swap fuel gauge reset: After installing this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100%. The fuel gauge IC on both tablets calibrates against the old cell's wear data — one full cycle resets it to the new cell and resolves the inaccurate percentage readout that appears immediately after a swap.

Tablet shutting down at 15–25% remaining after battery swap

This happens because the fuel gauge IC still holds calibration data from the degraded original cell. When the display backlight and Wi-Fi radio pull current simultaneously, voltage dips sharply — the IC reads that dip against the old cell's curve and triggers a low-battery shutdown even though charge remains. The fix is one full discharge-to-cutoff cycle followed by an uninterrupted charge to 100%. After that cycle, the IC maps the new cell's voltage curve and shutdowns stop occurring before the true low-voltage floor.

Fast charging unavailable after installing the replacement cell

The charge IC on the M2 and V9+ uses a handshake with the charger during the first accepted charge cycle to confirm cell compatibility before enabling higher charge rates. If the first charge after a swap was interrupted or the tablet was in use during charging, that negotiation may not have completed. Plug into the original Билайн charger, leave the tablet idle and undisturbed, and allow a full charge to 100%. Fast charge availability is confirmed once the first uninterrupted cycle completes.