About this replacement
Samsung Galaxy Tab Active 5 — 3.85V Li-Polymer Replacement Battery (EB-BX306GBY)
This 3.85V, 4800mAh Li-Polymer battery replaces the EB-BX306GBY / GH43-05200A cell in the Samsung Galaxy Tab Active 5. It fits both the WiFi (SM-X300) and 5G (SM-X306) variants. Install it when the original cell no longer holds sufficient charge or the tablet fails to power on.
- SM-X300 and SM-X306 compatibility: Both WiFi and 5G variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell covers both boards without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the SM-X306 board. The BMS accepted the cell without fault flags, charge current ramped normally through CC/CV stages, and the protection circuit tripped correctly at low-voltage cutoff.
- Fuel gauge recalibration after swap: After installation, run one full discharge to automatic shutoff, then charge uninterrupted to 100%. This resets the fuel gauge IC calibration against the new cell and clears the inaccurate percentage readings that commonly appear after a swap.
Galaxy Tab Active 5 shutting down at 15–25% remaining
The Active 5 combines a high-brightness display with always-on WiFi scanning — a combined load that creates a sharp voltage drop in the lower charge range. The fuel gauge IC, still calibrated to the worn original cell, reads the voltage cliff incorrectly and triggers an early shutdown. A new cell with a flatter discharge curve eliminates the cliff, but the gauge needs one full cycle to map it accurately. After that recalibration cycle, the tablet tracks remaining charge correctly down to shutoff.
Fast charging not available after battery replacement
Samsung's adaptive fast charge requires the charge IC to complete at least one accepted charge handshake with the new cell before enabling higher current delivery. If the tablet reverts to standard 5W charging immediately after installation, this is expected behaviour. Plug into the original Samsung charger — not a third-party adapter — and let the first cycle complete fully without interruption. On the next charge the USB-PD negotiation will engage and fast charge will be available again.