Redmi K30 Replacement Battery 3.85V 4400mAh Li-Polymer

Redmi K30 / K30 5G (M2001G7AE, M2001G7AC) — 3.85V Li-Polymer Replacement Battery

This 3.85V, 4400mAh Li-Polymer cell replaces the original battery in the Redmi K30 and K30 5G smartphones, including variants M2001G7AE and M2001G7AC. It covers the full voltage rail the board expects and matches the physical footprint at 86.30 × 64.50 × 4.25mm. Capacity figures come from the product data — 16.94Wh at rated voltage.

• K30 and K30 5G platform fit: Both the LTE and 5G variants of the K30 share the same battery bay dimensions and 3.85V nominal voltage rail. The connector pinout and BMS communication protocol are identical across M2001G7AE and M2001G7AC, so one cell covers both boards.
• Bench tested on actual hardware: We ran this cell on a K30 board and confirmed the BMS handshake completes at power-on, charge IC accepts the cell without flagging an error, and the fuel gauge IC begins tracking coulomb count from the first charge cycle.
• First-cycle fast charge protocol: On first use after installation, disable fast charging and run one full discharge-to-charge cycle at standard current. This lets the fuel gauge IC recalibrate its discharge curve against the new cell before Redmi's proprietary fast-charge protocol pushes high current into an uncalibrated cell.

Sudden shutdown at 20–30% on the Redmi K30 after a cell swap

The K30's fuel gauge IC stores a learned discharge curve from the original cell. A new cell has a steeper voltage cliff at lower state-of-charge, and the old curve does not account for it. When the modem transmits or the display brightness spikes, current draw pulls cell voltage below the 3.2V BMS cutoff faster than the gauge predicts — triggering an abrupt shutdown even though the percentage readout still shows charge remaining. One complete slow discharge-charge cycle overwrites the stored curve and eliminates most of these events.

USB-PD or fast charge not accepted on the first cycle after replacement

The charge IC on the K30 checks cell impedance before enabling fast-charge mode. A new Li-Polymer cell has higher internal impedance than a broken-in cell, and the IC can interpret this as a fault condition, reverting to standard 5V slow charging. This is not a defective cell — it clears itself after one or two full charge cycles as impedance settles. If fast charging still does not activate after two cycles, check the USB-C port for debris and confirm the cable supports the rated current.