Neo V12 ThLV12 Compatible Battery 3.7V 1800mAh

Neo V12 / MC-V12 — 3.7V Li-Polymer Replacement Battery (ThLV12)

This 3.7V, 1800mAh lithium-polymer cell replaces the original battery in the Neo V12 and MC-V12 smartphones. It matches the OEM part number ThLV12 and fits the physical bay at 65.30 × 54.24 × 4.70 mm. Voltage and connector pinout match the stock configuration — no modification needed.

• V12 and MC-V12 platform fit: Both models share the same battery bay dimensions, connector layout, and BMS handshake protocol. A single cell variant covers both — no hardware difference between the two at the battery interface.
• Bench tested on actual hardware: We ran the ThLV12 cell through charge and discharge cycles on the V12 platform. The BMS accepted the cell without error flags, and the charge IC stepped through pre-charge, constant-current, and constant-voltage phases cleanly.
• Fuel gauge recalibration after swap: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Why the Neo V12 reports wrong battery percentage after a cell swap

The V12 uses a fuel gauge IC that builds its charge model from the previous cell's discharge history. When you fit a new cell, the IC still holds the old curve in memory. Until a full discharge-to-charge cycle resets the coulomb counter, the percentage reading will drift — sometimes by 15–20%. One complete cycle from near-zero to 100% at standard charge current corrects this. After that cycle, the reported percentage should track actual cell voltage accurately.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC hasn't recalibrated yet and the phone hits the voltage cliff earlier than expected. Under modem transmit or screen-load spikes, cell voltage briefly drops below the BMS low-voltage cutoff — even though the displayed percentage looks safe. The BMS interprets this as a critically low-voltage event and shuts the device down. Run the recalibration cycle first; if shutdowns persist after that, measure resting cell voltage — it should read above 3.6V at 30% indicated charge.