Canon BP-308 Replacement Battery 7.4V 850mAh Li-ion

Canon DC51 / Optura 600 / IXY DVM5 — 7.4V Li-ion Replacement Battery (BP-308)

This 7.4V, 850mAh Li-ion battery replaces the Canon BP-308, BP-308B, and BP-308S cells. It fits the DC51, IXY DVM5, DMVX4i, and Optura 600 compact camcorders. Same dimensions at 62.90 × 40.32 × 9.67mm — it seats and latches exactly as the original does.

• DC51 and Optura 600 platform compatibility: These camcorders share the same BP-308 battery rail, connector pinout, and BMS handshake protocol. One cell covers all four models listed without any adapter or modification.
• Bench tested on actual hardware: We cycled this cell through a Canon DC51 body and monitored BMS communication, charge acceptance, and cutoff behaviour. The protection circuit tripped correctly at both the high-end charge ceiling and the low-voltage discharge floor.
• First-install charge cycle on Canon camcorders: Insert the battery and run a full charge inside the Canon charger or camera body before your first shoot. Canon's BMS maps battery-remaining percentages against a discharge curve it learns on that first full cycle — skipping it causes the indicator to read inaccurately from the start.

Canon BMS rejecting a third-party cell on first install

Canon camcorders in this range run an authentication check when a new cell is seated. A replacement cell that hasn't been through a full charge cycle in the Canon charger can trigger a rejection flag — the camera either displays a battery warning or refuses to power on. This isn't a fault with the cell itself. Connect the battery to the Canon charger, let it reach a full charge (indicator light goes solid), then insert it into the camera body. That single cycle clears the flag in most cases.

Battery percentage jumping erratically on the DC51 display

The DC51's fuel gauge maps display segments against a fixed discharge voltage curve calibrated to the original BP-308 cell. A new replacement cell can have a slightly different discharge curve, causing the indicator to jump — showing 60%, then dropping to 20% after one short clip. This isn't the cell losing charge; it's the BMS recalibrating its internal model. Run two or three full charge-discharge cycles and the display stabilises as the camera's BMS adapts to the new cell's actual curve. After conditioning, the resting voltage at "one bar" should sit at approximately 7.0V.