About this replacement
BlackView BV8000 — 3.8V Li-Polymer Replacement Battery (V636468P)
This 3.8V, 4100mAh lithium-polymer cell replaces the factory battery in the BlackView BV8000 rugged smartphone. It carries OEM part number V636468P and fits the BV8000 directly. Rated at 15.58Wh, it powers the display, processor, modem, and all onboard features.
- BV8000 fitment: The BV8000 uses a sealed rear housing with a fixed connector pinout tied to this cell format. The V636468P matches that connector, the physical 67.80 × 62.90 × 6.00mm envelope, and the BMS communication the phone expects from the battery management circuit.
- Bench tested on actual hardware: We cycled this cell through a full discharge and charge sequence on the BV8000 platform. The BMS accepted the cell without error, charge termination triggered correctly at 4.35V, and the fuel gauge IC tracked state of charge without jumping.
- First-cycle recalibration tip: On first use after installation, disable fast charging and complete one full discharge-to-charge cycle. This lets the fuel gauge IC build a baseline discharge curve against the new cell before high-current charging pushes current into an uncalibrated state-of-charge register.
Why the BV8000 reports wrong battery percentage after a cell swap
The BV8000 uses a coulomb-counter fuel gauge IC that stores a learned discharge curve from the original cell. When a new cell goes in, the IC still references that old curve. The result is percentage readings that drift, spike, or plateau at values that don't match actual charge state. One full discharge below 10% followed by a complete charge to 100% forces the IC to re-map the curve against the new cell's actual chemistry and capacity. After that cycle, percentage accuracy typically stabilises within two to three additional charges.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem or display draws a short high-current spike and the cell voltage briefly drops below the BMS protection threshold — even though the gauge still shows charge remaining. It is a voltage-sag issue, not a capacity issue, and it is most common before the fuel gauge IC has recalibrated. The phone interprets the voltage dip as a hard undervoltage event and shuts down to protect the cell. Complete two full discharge-charge cycles, then check whether the shutdowns continue; if they do, verify that the resting cell voltage after a full charge reads at or above 4.30V.