Vivo BA10 Y17S Replacement Battery 3.89V 4850mAh

Vivo Y17S / V36m Series — 3.89V Li-Polymer Replacement Battery (BA10)

The BA10 is the OEM-matching Li-Polymer cell for the Vivo Y17S, V36m, V2318A, and V2310 smartphones. It runs at 3.89V with a capacity of 4850mAh (18.87Wh). Swap it in when the original cell degrades, swells, or can no longer hold a usable charge.

• Y17S / V36m platform fit: These four models share the same battery bay geometry, connector pinout, and BMS handshake protocol. The BA10 part number covers all of them — the same cell voltage rail and NTC thermistor wiring runs across the V2318A and V2310 variants.
• Bench tested on actual hardware: We cycled this cell on a V2318A unit and confirmed full charge acceptance, BMS communication with the charge IC, and clean overvoltage cutoff at 4.40V. The fuel gauge IC recognised the new cell and began coulomb counting immediately after the first full cycle.
• First-cycle fast charge protocol: On first use after installation, disable fast charging and complete one full discharge-charge cycle at standard rate. This lets the fuel gauge IC recalibrate its discharge curve against the new cell before high-current fast charging loads an uncalibrated state-of-charge map.

Sudden shutdown at 20–30% on the Y17S after a cell swap

A new BA10 cell has a steeper voltage-discharge curve than the aged cell the fuel gauge IC was calibrated against. Under modem or display load, the cell voltage drops quickly past the hardware cutoff threshold before the OS percentage reading catches up. The phone shuts off while the gauge still reads 20–30%. One full uninterrupted discharge-charge cycle at standard rate recalibrates the coulomb counter and pulls the cutoff point back into alignment. After that cycle, shutdowns below 15% are normal — shutdowns above that indicate a wiring issue at the connector.

USB fast charge not activating on the first charge after replacement

Vivo's proprietary fast-charge handshake requires the BMS on the new cell to complete its first charge cycle in a known state before the charge IC enables elevated current. On the first connection, the charge IC sees an uncalibrated BMS and defaults to standard 5V/1A input as a protective measure. Plug in using the original Vivo adapter, allow the battery to reach 100% without interruption, then unplug and reconnect — fast charge should activate on the second connection. If it still does not trigger, check that the adapter output is at least 10W and the cable supports the required current rating.