About this replacement
Samsung Galaxy Tab S9 Ultra — 3.88V Li-Polymer Replacement Battery (EB-BX916ABY)
This is a 3.88V, 10800mAh (41.9Wh) Li-Polymer replacement battery for the Samsung Galaxy Tab S9 Ultra. It fits the SM-X910, SM-X910N, SM-X916, and related variants. Replace a degraded original cell when the tablet no longer holds charge or shuts down unexpectedly under load.
- SM-X910 and SM-X916 series compatibility: Both Wi-Fi and 5G variants of the Tab S9 Ultra share the same battery bay dimensions, connector pinout, and BMS communication protocol — that is why a single cell (EB-BX916ABY) covers the full lineup.
- Bench tested on actual hardware: We installed this cell in an SM-X910 unit and cycled it through full charge and discharge. The BMS negotiated correctly with the charge IC, accepted fast charge input, and held voltage above 3.6V through a combined display-plus-wireless load test.
- Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without unplugging. This single full cycle recalibrates the fuel gauge IC against the new cell and clears the inaccurate percentage readings that almost always appear straight after installation.
Why the Tab S9 Ultra shuts down at 15–25% remaining after a battery swap
The Galaxy Tab S9 Ultra's fuel gauge IC was calibrated to the resistance curve of the original cell. A new cell has a different internal resistance profile, so the IC reads voltage incorrectly under the combined load of the 14.6-inch Dynamic AMOLED panel and active Wi-Fi or 5G radio. When the display and wireless stack both draw simultaneously, the battery voltage dips briefly below the IC's shutdown threshold — even though usable charge remains. One full recalibration cycle (discharge to shutoff, uninterrupted charge to 100%) corrects this. After that cycle, shutdowns in the 15–25% range stop.
Fast charging unavailable on the Tab S9 Ultra after battery replacement
The Tab S9 Ultra uses USB-PD and Samsung's proprietary 45W charging protocol. After a battery swap, the charge IC sometimes defaults to standard 5W input until it completes one accepted charge cycle with the new cell. This is a handshake issue, not a fault with the replacement battery or the charger. Plug in the original Samsung 45W USB-C adapter — third-party chargers may not trigger the full PD negotiation — and allow one complete charge from low to 100%. Fast charge availability is typically restored after that first accepted cycle.