RADIWOW R-108 Replacement Battery 3.7V 1200mAh Li-ion

RADIWOW R-108 — 3.7V Li-ion Replacement Battery

This 3.7V, 1200mAh Li-ion cell replaces the original battery in the RADIWOW R-108 portable radio receiver. It matches the original voltage and physical footprint at 53.00 x 33.90 x 5.70mm. Capacity figure is taken from the product specification — 4.44Wh.

• R-108 fit and voltage rail: The R-108 runs a single-cell 3.7V Li-ion architecture. This replacement matches that voltage rail exactly. A mismatch here would push the radio's internal regulator out of spec and cause audio distortion or no output at all.
• Bench tested on actual hardware: We cycled this cell through the R-108's charge circuit and confirmed the BMS accepted the charge handshake without flagging a fault. Discharge held stable voltage through the radio's tuner and amplifier stages with no cutoff event.
• Fuel gauge recalibration after install: After fitting this cell, run one complete discharge down to automatic shutoff, then charge uninterrupted to 100% before normal use. The R-108's fuel gauge IC was calibrated against the old cell's discharge curve — skipping this step causes percentage jumps and early low-battery warnings.

Why the R-108 shuts off suddenly at 20–30% after a cell swap

The R-108's fuel gauge IC stores a discharge curve from the original cell. A new cell has a different internal resistance profile, so the IC underestimates remaining capacity. Under load — when the tuner locks onto a signal and the amplifier draws peak current — the voltage sags below the cutoff threshold even though the displayed percentage still reads 20–30%. The IC hasn't mapped the new cell's actual knee voltage yet. One full discharge-charge cycle forces the coulomb counter to rebuild its reference curve against the new cell.

R-108 shows incorrect battery percentage after replacement

This happens because the fuel gauge IC recalibrates continuously against historical charge and discharge data. Swapping the cell resets that history to a mismatch. The displayed percentage can jump erratically — sometimes reading full, then dropping ten points in seconds. This is a calibration state, not a fault with the cell. Discharge the R-108 completely until it shuts itself off, then charge to 4.2V in one uninterrupted session to reset the fuel gauge baseline.