Infocus M512 Replacement Battery 3.8V 2500mAh

Infocus M512 — 3.8V Li-Polymer 2500mAh Replacement Battery

This is a 3.8V Li-Polymer replacement battery for the Infocus M512 smartphone. It carries a 2500mAh capacity, matching the original cell specification. When the factory battery no longer holds a charge or shuts down unexpectedly, this cell restores full operation without replacing the phone.

• Infocus M512 fitment: The M512 uses a specific 73.10 x 54.13 x 4.40mm cell footprint with a three-contact connector wired to the phone's charge IC and fuel gauge IC. This cell matches that connector pinout and physical envelope — the BMS can read cell state correctly once calibrated.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the M512 platform, monitoring BMS handshake, charge cutoff voltage, and cell response under screen-on and modem load. The cell accepted the full charge profile without cutoff errors.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before any high-current session pushes current into an uncalibrated cell.

Sudden shutdown at 20–30% on the M512 after a cell swap

The M512's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell has a slightly different voltage-to-capacity profile, so the IC can misread remaining charge. Under heavy load — screen on full brightness plus active data — the cell voltage drops faster than the IC expects. The phone interprets this as a low-voltage condition and shuts down, even though the percentage shown looks safe. One full discharge-charge cycle at standard current resets the coulomb counter and corrects the curve. After that cycle, shutdowns at 20–30% typically stop.

Phone warm near the battery compartment on first charge after replacement

A new high-impedance Li-Polymer cell generates slightly more heat in the first charge cycle than a conditioned cell. The M512's charge IC applies full current into a cell whose internal resistance it has not yet characterised. This is normal and typically resolves after the first complete cycle as the charge IC adjusts. If the case feels hot to hold — not just warm — disconnect the charger and let the phone cool to room temperature before resuming. After one full cycle, charge temperature should return to the level you saw with the original battery.