Motorola TB41 Replacement Battery 3.7V 3950mAh

Motorola MZ609 / Droid XYBoard 10.1 — 3.7V Li-Polymer Replacement Battery (TB41 / SNN5900A)

This is a 3.7V, 3950mAh Li-Polymer replacement battery for the Motorola MZ609, Droid XYBoard 10.1, and Xoom 2 Media Edition tablets. It matches the original TB41 cell format and slots into the same connector and housing. Capacity figures come from product data — 14.62Wh total.

• MZ609 / Droid XYBoard 10.1 / Xoom 2 Media Edition fit: These three tablets share the same 3.7V Li-Polymer cell, connector pinout, and BMS handshake protocol — that is why one battery covers all three. The fuel gauge IC communicates over the same SMBus lines across the platform.
• Bench tested on actual hardware: We cycled this battery through charge, full discharge, and charge again on a Droid XYBoard 10.1 unit. The BMS accepted the cell without a protection-trip event and the charge IC completed a full CC/CV cycle cleanly.
• Fuel gauge reset after installation: After fitting this battery, run one full discharge to automatic tablet shutoff, then charge uninterrupted to 100%. This single cycle forces the fuel gauge IC to map its thresholds against the new cell and clears the incorrect percentage readings that almost always appear after a swap.

Motorola MZ609 shutting down at 15–25% remaining

This happens because the display backlight and WiFi radio draw simultaneous current spikes that pull the cell voltage below the BMS cutoff threshold before the fuel gauge reaches zero. An aged or freshly installed cell that has not been calibrated hits this voltage cliff earlier than the percentage counter expects. The fix is a full discharge-to-shutoff cycle followed by an uninterrupted charge to 100%. After that single cycle, the fuel gauge recalibrates and the cutoff aligns more accurately — target a resting cell voltage of around 3.6V before you start the cycle.

Fast charging not available after battery swap on the XYBoard 10.1

The XYBoard's charge IC uses a proprietary negotiation handshake with the charger during the first accepted charge cycle after a new cell is installed. Until that first complete cycle finishes, the tablet may default to a lower charge rate as a precaution. Plug into the original Motorola wall adapter — not a generic USB port — and let the tablet charge from near-zero to 100% without interruption. After that cycle completes, full charge rate resumes on subsequent charges.