Panasonic EB-BSD92B GD92 Replacement Battery 3.7V 700mAh

Panasonic GD92 / GD80 / TX310 — 3.7V Li-ion Replacement Battery (EB-BSD92B)

This is a 3.7V, 700mAh Li-ion replacement for the Panasonic EB-BSD92B cell. It fits the GD92, GD80, and TX310 handsets — compact candybar and clamshell phones from Panasonic's early GSM lineup. Voltage and capacity match the original spec exactly.

• GD92, GD80, and TX310 compatibility: All three models run the same 3.7V single-cell Li-ion architecture with a shared connector footprint and BMS handshake protocol. One cell fits the entire group without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the GD92 platform. The BMS accepted the cell cleanly, charge termination triggered correctly at 4.2V, and the protection circuit responded normally to load.
• 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 recalibrate against the new cell's discharge curve before any high-current charging pushes current into an uncalibrated cell.

Why the GD92 reports wrong battery percentage after a cell swap

The GD92 uses a fuel gauge IC that tracks charge state by measuring cumulative current flow — a coulomb counter approach. When the original cell ages, the IC recalibrates its full-charge reference down to match the degraded capacity. A new 700mAh cell has a different discharge curve, so the IC's stored reference is wrong. The phone will show inaccurate percentages — often reading full too quickly or dropping suddenly — until one complete discharge-charge cycle forces the IC to reset its endpoints against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC still holds the old cell's voltage-to-capacity map. Under modem load or screen backlight draw, the new cell's voltage can sag faster than the IC predicts, triggering a protective shutdown before the displayed percentage reaches zero. It is not a fault with the cell itself. Run one full discharge to the auto-off point, then charge uninterrupted to 100% — this resets the IC's low-voltage cutoff reference and stops premature shutdowns.