Samsung VP-HMX10 Replacement Battery IA-BP85ST 7.4V 850mAh

Samsung VP-HMX10 Series — 7.4V Li-ion Replacement Battery (IA-BP85ST)

This is a 7.4V, 850mAh Li-ion replacement for the Samsung IA-BP85ST battery pack. It fits the VP-HMX10, SC-HMX10A, SC-MX10R, VP-MX10AU, and 17 additional Samsung compact camcorder models. Direct swap for a degraded original cell that no longer holds usable charge during recording or playback.

• VP-HMX10 and SC-MX10 series fit: These models share a common 7.4V battery bay, connector pinout, and BMS communication protocol — which is why one SKU covers the full range. The cell dimensions (39.50 × 39.10 × 13.30mm) match the cavity exactly, so the door closes without force.
• Bench tested on actual hardware: We cycled this cell through the VP-HMX10 body. The BMS accepted the cell on first insertion, charge termination triggered cleanly at full capacity, and the battery-remaining indicator tracked consistently through discharge.
• First-use charge cycle on HMX-series bodies: Run the first full charge inside the camera body rather than a standalone charger. The HMX-series BMS maps voltage thresholds to the display indicator during an in-body charge — skipping this step can cause the battery bar to read full and then drop sharply mid-session.

Why the VP-HMX10 shows a dead battery icon on a partially charged replacement cell

The HMX10 body uses a voltage-curve map stored in firmware to estimate remaining charge. A new Li-ion cell has a slightly different resting voltage profile than a worn original, so the camera can misread the state of charge on first use. The indicator may show empty even when the cell is at 60–70% capacity. One full in-body charge cycle recalibrates the map and resolves the mismatch. After that cycle, the display tracks accurately through a normal discharge.

Battery percentage jumping erratically during recording

This happens when the camera's fuel gauge hasn't matched the new cell's discharge curve yet. The VP-HMX10 draws variable current — higher during active recording, lower during standby — and the indicator can spike or drop when the firmware references stale threshold data. It is not a fault with the cell itself. Charge the battery fully via the camera body, run it down to auto-shutoff, then charge again fully. After two complete cycles the percentage reading stabilises.