Mustek DC300 Replacement Battery 3.7V 1000mAh Li-ion

Mustek DC300 / DC500 Series — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1000mAh Li-ion cell for the Mustek DC300, DC500, DC500T, DC-500T, and compatible models in the same series. It fits cameras sharing the same battery bay dimensions and voltage rail. Capacity is 1000mAh (3.7Wh), matching the original cell specification.

• DC300 / DC500 series compatibility: These models share the same physical bay (52.95 × 33.07 × 8.01mm), voltage rail, and connector pinout. A single cell covers the full range without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on compatible hardware and confirmed the protection circuit trips correctly at low-voltage cutoff. The BMS held within expected thresholds across multiple cycles.
• Fuel gauge recalibration after install: After fitting a new cell, run one full discharge to camera shutoff, then charge uninterrupted to 100% before use. The camera's fuel gauge IC was calibrated to the old cell's discharge curve — skipping this step produces inaccurate percentage readings from the first shot.

Sudden camera shutoff with charge still showing on screen

A fresh Li-ion cell has a steeper voltage discharge curve than a broken-in cell. When the camera draws a burst of current — writing a large file or firing the flash — voltage sags sharply. If the camera's low-voltage cutoff threshold sits higher than the sag floor, it reads the drop as a dead cell and cuts power. This is normal behaviour on the first few cycles. After two or three full discharge-charge cycles, the cell's internal resistance drops and voltage sag under load stabilises.

Battery percentage stuck or jumping after replacement

The camera stores a charge curve model in firmware tied to the old cell's impedance profile. A new cell has different internal resistance, so the coulomb counter misreads state-of-charge and reports erratic percentages. The fix is one full uninterrupted charge to cutoff, followed by a discharge to camera shutoff. After that cycle, the fuel gauge IC resets its reference points against the new cell and percentage tracking stabilises near 3.7V nominal.