JVC BN-V812 GR-DLS1U Replacement Battery 7.4V 3400mAh

JVC GR-DLS1U / GR-DVL Series — 7.4V Li-ion Replacement Battery (BN-V812)

This is a 7.4V, 3400mAh Li-ion battery pack for JVC camcorders including the GR-DLS1U, GR-DV9000, GR-DVL, and GR-DVL9000. It replaces OEM part numbers BN-V812, BN-V812U, BN-V814, and BN-V814U. The connector and cell voltage match the original spec so the camera body accepts the pack without modification.

• GR-DVL and GR-DV9000 compatibility: These models share the same 7.4V battery bay, connector pinout, and BMS communication protocol — which is why a single pack covers the full series. Swapping between models in this family does not require a different cell configuration.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on the GR-DLS1U body. The BMS handshake completed cleanly on first insertion, and the battery indicator reported charge state accurately across the full discharge curve without erratic jumps.
• First-install charge cycle on GR-DVL bodies: JVC's BMS on DVL-series bodies calibrates the battery-remaining display during the first charge from within the camera body — not from an external charger. Charge the new pack in the camera itself on first use, not in a standalone dock, or the percentage gauge may read incorrectly from the start.

Why the GR-DLS1U battery indicator drops suddenly during recording

The GR-DLS1U uses a voltage-threshold system to estimate remaining charge. During active recording, the combined draw from the CCD sensor, LCD panel, and tape transport pulls voltage down faster than the indicator can compensate. A cell near end-of-life shows this as a sudden step-drop from 50% to near-zero rather than a gradual decline. A fresh 3400mAh cell holds voltage above the threshold longer, so the indicator stays stable through most of a recording session.

Camera displays dead-battery icon immediately after inserting a charged replacement

This happens when the camera body has not yet completed a BMS authentication cycle with the new cell. The GR-DVL series in particular requires one full charge cycle through the camera body before it maps the cell's discharge curve correctly. Remove the pack, reinsert it, and place the camera on charge via its DC-in port until the charge indicator clears. After that first cycle, the body will read the pack's state accurately — resting voltage on a fully charged pack should measure 8.3–8.4V at the terminals.