Sigma BP-51 Compatible Battery DP1Q 7.4V 800mAh

Sigma DP1Q / DP2Q / DP3Q — 7.4V Li-ion Replacement Battery (BP-51)

This is a 7.4V, 800mAh Li-ion cell built to the BP-51 specification. It fits the Sigma DP1Q, DP2Q, and DP3Q compact cameras. Slide it into the same battery compartment as the original and it connects to the same BMS handshake points.

• DP Quattro series fit: The DP1Q, DP2Q, and DP3Q share the same battery bay geometry and the same 7.4V power rail. One BP-51 cell covers all three bodies without modification.
• Bench tested on actual hardware: We ran this cell through the Sigma BMS authentication cycle and confirmed the charge circuit accepted it without rejection flags. The protection board responded correctly to both low-voltage cutoff and overcharge thresholds.
• First-cycle conditioning on the Quattro body: Insert this cell and run one full charge cycle through the camera body or OEM charger before your first shoot. Sigma's battery-remaining indicator maps voltage thresholds to shot-count estimates — it needs one complete cycle from this specific cell's discharge curve to display an accurate reading.

Why the DP Quattro body shows a dead-battery icon on a partially charged replacement cell

The Quattro's battery indicator does not read raw voltage in a simple linear way. It compares the incoming voltage to a stored discharge curve from the last recognised cell. A new BP-51 cell with no stored history can register as depleted even at 7.2V because the camera has no reference curve to map it against. Run one full charge cycle — from empty to 8.4V — inside the camera or OEM charger. After that cycle, the body stores the new cell's profile and the indicator reads accurately.

Battery percentage jumping between shots during a shoot

This happens when the camera's fuel gauge samples voltage during high-current events — autofocus motor drive, sensor readout, and the Foveon X3 processing load all spike current draw simultaneously. Voltage sags briefly under that load, and the indicator interprets the sag as a capacity drop. It then corrects upward when current draw falls between shots. This is a display artefact, not a fault with the cell. If the jumps are large and persistent rather than settling, check resting voltage with a multimeter — a healthy cell at 50% charge sits at approximately 7.2V.