About this replacement
Huawei MediaPad M5 — 3.85V Li-Polymer Replacement Battery (HB299418ECW)
This is a 3.85V, 7300mAh (28.11Wh) lithium-polymer battery for the Huawei MediaPad M5 and MediaPad M5 10.8, covering CMR-AL09 and CMR-AL19 variants. It replaces OEM part HB299418ECW directly. Fit this when the original cell no longer holds a full charge or the tablet shuts down unexpectedly under load.
- MediaPad M5 and M5 10.8 compatibility: Both the 8.4-inch and 10.8-inch M5 variants use the same HB299418ECW cell, same connector, and the same charge-management IC handshake. One replacement covers all listed model codes.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the M5 platform. The BMS accepted the charge IC handshake without error flags, and cell voltage held stable across display-on and WiFi-active load states.
- Fuel gauge recalibration after swap: After fitting, run the tablet down to automatic shutoff — do not force it off — then charge uninterrupted to 100%. This resets the fuel gauge IC against the new cell's actual capacity curve and clears the inaccurate percentage readings that appear after a swap.
Tablet shutting down at 15–25% remaining after battery replacement
This happens because the fuel gauge IC is still calibrated to the old cell's voltage-to-capacity curve. When the new cell hits a voltage point the IC previously mapped to near-empty, it triggers a shutdown — even though real charge remains. The fix is one full discharge-to-shutoff followed by an uninterrupted charge to 100%. After that cycle, the IC re-anchors its calibration to the new cell, and shutdowns at false percentages stop.
Fast charging not available after fitting the new battery
Huawei's SuperCharge protocol requires a completed charge cycle before the charge controller unlocks higher current delivery on a new cell. Immediately after swap, the tablet may only accept standard 5V input. Plug in the original Huawei charger — third-party adapters often fail USB-PD negotiation on this platform — and allow one full charge cycle to complete. SuperCharge should activate on the next session once the controller has accepted the cell.