About this replacement
Toshiba V904T / 811T / 810T Series — 3.7V Li-ion Replacement Battery (TSBAE1)
This is a 3.7V, 950mAh Li-ion cell that replaces the original battery in the Toshiba V904T, 811T, 810T, and TX8 series mobile phones. The TSBAE1 part number covers the shared battery platform across these compact handsets. Capacity figure is 950mAh (3.52Wh) — taken from product data, not estimated.
- V904T / 811T / 810T / TX8 shared platform: These models use the same 3.7V single-cell architecture and identical connector pinout, which is why one part number covers all of them. The BMS handshake parameters match across the range — no firmware variation between units affects cell acceptance.
- Bench tested on actual hardware: We cycled this cell through a full discharge-charge sequence and monitored BMS communication. The protection circuit engaged correctly at low-voltage cutoff, and charge termination fired at the expected threshold without overrun.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging if your carrier or software permits it, and run one complete discharge-charge cycle. This lets the fuel gauge IC build an accurate discharge curve against the new cell before the OS starts reporting percentages users will trust.
Why the V904T reports wrong battery percentage after a cell swap
The fuel gauge IC on the V904T stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The OS reads fuel gauge data directly, so it displays percentages calibrated to the old cell — not the new one. One full discharge down to auto-shutdown followed by a complete charge resets the coulomb counter and forces the IC to rebuild its curve against the new cell's actual behaviour.
Sudden shutdown at 20–30% remaining on the replacement cell
This happens when the cell voltage drops sharply under load — the modem transmitting or the screen at full brightness — before the fuel gauge has recalibrated. A fresh cell with an uncalibrated IC can report 25% while the actual open-circuit voltage has already fallen close to the BMS cutoff threshold of around 3.0V. The protection circuit trips to prevent cell damage, and the phone cuts off instantly without a low-battery warning. Run one full calibration cycle and the reported percentage will align with real voltage levels — shutdowns at falsely high percentages stop after that.