About this replacement
Sunmi M2 Max — 3.85V Li-Polymer Replacement Battery (JKLK)
This is a 3.85V, 8400mAh lithium-polymer battery for the Sunmi M2 Max commercial Android tablet. It fits the M2 Max and P10010016 model variants. Swap this in when the original cell has degraded and the tablet can no longer hold a full working charge.
- M2 Max and P10010016 compatibility: Both variants use the same battery bay geometry, connector pinout, and charge IC handshake. The JKLK part number is the shared OEM reference across the M2 Max line — no adapter or modification needed.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the M2 Max platform. The BMS accepted the charge IC handshake on first connection, voltage held stable under combined display and WiFi load, and protection thresholds tripped correctly at low-voltage cutoff.
- Fuel gauge recalibration after swap: After installation, run the tablet down to automatic shutoff, then charge uninterrupted to 100% without using the device. This forces the fuel gauge IC to recalibrate against the new cell's actual capacity curve and clears the inaccurate percentage readings that appear immediately after a battery replacement.
Tablet shutting down at 15–25% remaining after battery swap
This happens because the fuel gauge IC is still calibrated to the old cell's voltage curve. The new cell hits a voltage cliff under combined display, WiFi, and background process load — the tablet reads this drop as critically low and shuts down, even though capacity remains. It is not a fault with the replacement cell. Run one full discharge to automatic shutoff followed by an uninterrupted charge to 100%, and the shutdowns will stop. After that cycle, the IC maps the correct low-voltage threshold at approximately 3.5V per cell.
Fast charging not available on the M2 Max after a battery replacement
USB-PD negotiation on the M2 Max requires at least one completed charge cycle before the charge controller steps up to higher wattage with a new cell. On the first charge after installation, the controller runs a conservative profile while it characterises the new cell's internal resistance. Plug in, let the tablet charge fully without interruption, and fast charge will be available from the second charge cycle onward. If it still does not appear, confirm the charger is the original Sunmi adapter — third-party chargers often fail USB-PD negotiation entirely.