Doro 8100 Replacement Battery DBZ-3000A 3.8V 2500mAh

Doro 8100 / 8100 Plus — 3.8V Li-Polymer Replacement Battery (DBZ-3000A)

This is a 3.8V, 2500mAh (9.5Wh) Li-Polymer battery for the Doro 8100, 8100 Plus, and DSB-0400 smartphones. It replaces OEM part DBZ-3000A when the original cell has degraded, fails to hold a charge, or causes sudden shutdowns. Dimensions are 76.00 × 59.00 × 4.10mm — verify these against your existing cell before fitting.

• 8100 and 8100 Plus compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol, which is why a single cell covers the full range including DSB-0400 variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 8100 platform. The BMS accepted the cell without error flags, and the charge IC negotiated current correctly through a full cycle.
• First-cycle fuel gauge reset: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before any high-current session pushes into an uncalibrated state.

Sudden shutdown at 20–30% on the Doro 8100

This is a voltage cliff issue, not a capacity issue. Under peak load — active call, screen on, cellular radio transmitting — the cell voltage sags below the BMS cutoff threshold even though the fuel gauge still shows charge remaining. The old cell's internal resistance is too high to sustain the voltage rail under that current draw. A fresh cell with lower internal resistance holds the voltage rail above the cutoff and eliminates these shutdowns.

OS reporting wrong battery percentage after a cell swap

The fuel gauge IC on the 8100 uses a coulomb counter calibrated to the discharge curve of the old cell. When you fit a new cell, those reference points no longer match the actual cell chemistry, so the percentage readout drifts or jumps. Run one full discharge — down to auto-shutdown — followed by a full uninterrupted charge to 100%. After that single cycle, the IC resets its reference and percentage accuracy returns to normal.