About this replacement
BBK VIVO Y11 / Y11T — 3.8V Li-ion Replacement Battery (BK-B-60)
This is a 3.8V, 1700mAh Li-ion cell replacing part number BK-B-60 in the BBK VIVO Y11 and VIVO Y11T smartphones. It fits both models directly, restoring full power to calls, messaging, and apps. Capacity figure is 6.46Wh at the rated voltage.
- VIVO Y11 and Y11T compatibility: Both models run the same 3.8V battery rail, share the BK-B-60 connector footprint, and use the same BMS handshake protocol — one cell covers both without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on VIVO Y11 hardware. The BMS accepted charge current correctly, voltage held steady under screen and modem load, and no cutoff events triggered during the test sequence.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC build an accurate discharge curve for the new cell before high-current charging begins pushing current into an uncalibrated state.
Sudden shutdown at 20–30% on the VIVO Y11 after a cell swap
This happens when the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a voltage cliff under modem or display load before the gauge catches it. The OS reads 25% but the cell voltage has already dropped below the BMS cutoff threshold. One full discharge-to-shutdown followed by a full charge to 100% resets the coulomb counter and clears this.
USB fast charge not activating on the first cycle after replacement
On first charge after a cell swap, the BMS on the new cell may not immediately negotiate the proprietary fast-charge handshake with the VIVO Y11 charge IC. The phone falls back to standard 5V/1A charging until the BMS completes its first full cycle. Let the battery charge to 100% at standard rate, then discharge normally — fast charge typically activates from the second cycle onward. If it still does not activate, check that the charger output is at least 9V/2A.