Mustek DC300 Replacement Battery 3.7V 750mAh Li-ion

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

This is a 3.7V 750mAh (2.78Wh) lithium-ion battery for the Mustek DC300, DC500, DC500T, and DC-500T compact digital cameras, plus nine additional models in the same series. It slots into cameras that have lost capacity or failed outright on the original cell. Voltage and physical dimensions — 53.49 × 33.44 × 6.91mm — match the original cell geometry.

• DC300 / DC500 series compatibility: These models share the same battery bay dimensions, 3.7V nominal voltage rail, and charge circuit — a single cell spec covers the full lineup without connector or BMS conflicts.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the DC500 platform. The BMS accepted charge from the camera's onboard charge IC without tripping, and cell voltage held stable at 4.19V at full charge termination.
• First-cycle discharge tip for DC-series cameras: After fitting this battery, shoot until the camera shuts itself off before recharging. The DC300 and DC500 use a basic fuel gauge that recalibrates its low-battery cutoff point against a full discharge — skip this and the camera may shut down early on subsequent charges.

Why the DC300 shuts off before the battery indicator hits empty

The DC300's fuel gauge was calibrated to the discharge curve of the original factory cell. A new cell — even at the same capacity — has a slightly different voltage-versus-charge curve. The camera's firmware reads voltage and maps it to a percentage using the old curve, so it can trigger a low-battery shutdown while the cell still holds usable charge. One full discharge-to-cutoff followed by a full charge resets the reference points the gauge uses. After that cycle, the indicator tracks the new cell accurately.

Camera won't power on after the replacement battery sat in storage

Li-ion cells ship at roughly 40–60% charge and self-discharge slowly in storage. If the battery dropped below 2.5V per cell before installation, the onboard BMS will have entered a lockout state to prevent damage — the camera will show no response at all. Connect the camera to its charger and leave it for 20–30 minutes without powering it on; the charge IC will trickle current into the cell until voltage rises above the BMS recovery threshold of approximately 2.9V. Once the BMS releases, normal charging resumes and the camera will power on.