About this replacement
Xiaomi Mi Pad 5 Pro — 3.87V Li-Polymer Replacement Battery (BN4D)
This is a 3.87V, 4200mAh (16.25Wh) Li-Polymer replacement battery for the Xiaomi Mi Pad 5 Pro and Mi Pad 5 Pro 5G tablets. It replaces OEM part number BN4D and fits the 11-inch display variant across both Wi-Fi and 5G models. Install it when the original cell no longer holds charge or causes unexpected shutdowns.
- Mi Pad 5 Pro and 5 Pro 5G compatibility: Both the Wi-Fi and 5G variants of the Pad 5 Pro use the same BN4D cell, identical 3.87V rail, connector pinout, and BMS handshake. One battery covers both SKUs.
- Bench tested on actual hardware: We cycled this battery through full charge and discharge passes on a Pad 5 Pro unit. The BMS accepted the cell without fault codes, charge IC communication held stable, and the protection circuit responded correctly to cutoff thresholds at both ends.
- Fuel gauge recalibration after swap: After fitting this battery, run the tablet down to automatic shutoff, then charge it uninterrupted to 100% without using the device. This gives the fuel gauge IC a full reference window against the new cell and corrects the inaccurate percentage readings that typically appear immediately after a replacement.
Tablet shutting down at 15–25% remaining after battery replacement
This happens because the fuel gauge IC was calibrated against the old, degraded cell. When a new cell is installed, the IC doesn't yet know where the real voltage cliff sits under combined display and Wi-Fi load. The tablet hits the hardware low-voltage cutoff before the OS percentage reaches zero, so it shuts off at what looks like 15–25% remaining. One full discharge-to-shutoff cycle followed by an uninterrupted charge to 100% resets the reference points and stops the early cutoff.
Fast charging unavailable after fitting a new BN4D cell
Xiaomi's proprietary fast charge protocol requires the charge IC and battery BMS to complete a handshake before the charger steps up power delivery. On a freshly installed cell, this handshake sometimes doesn't complete on the very first charge cycle. Use the original Xiaomi 67W adapter — not a third-party USB-PD charger — plug in and let the first charge run to 100% uninterrupted. Fast charge typically re-enables from the second cycle onward once the charge IC logs a completed session with the new cell.