About this replacement
Vivo V2412 / Y100 4G — 3.91V Li-Polymer Replacement Battery (BA43)
The BA43 is the OEM-matched Li-Polymer cell for the Vivo V2412 and Y100 4G smartphones. It runs at 3.91V nominal and delivers 4900mAh (19.16Wh). Install this when the original cell fails to hold charge or causes unexpected shutdowns.
- V2412 and Y100 4G platform fit: Both models share the same battery bay dimensions, flex connector pinout, and BMS handshake protocol — one cell covers both devices without modification.
- Bench tested on actual hardware: We cycled this cell on a V2412 unit and confirmed the BMS accepted charge negotiation on first connection, balancing correctly at 4.35V full-charge cutoff with no thermal flags during the initial cycle.
- 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 to the new cell's discharge curve before high-current charging pushes amps into an uncalibrated cell.
Sudden shutdown at 20–30% on a replacement BA43
This happens when the fuel gauge IC still holds the old cell's voltage-to-capacity curve in memory. The new cell hits a steeper voltage cliff under modem or display load than the old degraded cell did, so the phone shuts off before the percentage reaches zero. The fix is a full calibration cycle — drain the phone until it powers off automatically, then charge uninterrupted to 100% without pulling the cable. After one clean cycle, percentage readings should track actual cell voltage accurately.
USB fast charge not activating after installation
Vivo's proprietary fast charge protocol requires the charge IC to authenticate the battery BMS before boosting current above standard 5V/1A. On a fresh cell, this handshake sometimes fails on the first cycle because the BMS firmware initialises conservatively with an uncalibrated coulomb counter. Plug into the original Vivo charger — not a third-party adapter — and allow one full standard-rate charge to complete. Fast charge should activate automatically on the second connection once the BMS has logged a complete cycle.