Panasonic CGA-S004 Lumix DMC-FX2 Replacement Battery 3.7V

Panasonic Lumix DMC-FX2 Series — 3.7V Li-ion Replacement Battery (CGA-S004)

This is a 3.7V, 710mAh Li-ion cell replacing the CGA-S004 in the Panasonic Lumix DMC-FX2, DMC-FX2B, DMC-FX2EBS, DMC-FX2EG-S, and over a dozen related FX-series compact bodies. It matches OEM voltage and capacity spec exactly. Slot it into any camera or OEM charger that takes the original CGA-S004 form factor.

• FX-series compatibility: All listed DMC-FX bodies share the same CGA-S004 battery bay, connector pinout, and BMS communication protocol — that is why one cell covers the full range. Voltage rail is 3.7V nominal across every model on this list.
• Bench tested on actual hardware: We cycled this cell through the DMC-FX2 body and an OEM Panasonic charger. The BMS accepted the cell without error flags, and charge termination triggered correctly at full capacity on both platforms.
• First-cycle initialisation on FX-series bodies: Run the first full charge inside the camera body or OEM charger before shooting. The FX-series BMS maps battery-remaining percentage against a discharge curve it builds during that first cycle — skipping it causes the indicator to read erratically from the start.

Flash recycling slowing down before the battery indicator drops

The DMC-FX2 flash capacitor draws a sharp recharge current burst after every firing. As cell voltage sags under that burst load, the capacitor takes longer to reach full charge — even when the battery percentage still reads mid-range. This is a current-delivery limit, not a capacity problem. It appears earlier on cells that have accumulated shallow cycles, because internal resistance rises before usable capacity visibly falls. If flash recycle lag starts appearing, check resting cell voltage with a meter — anything below 3.6V at rest means the cell needs replacing.

Battery percentage jumping in large steps instead of counting down steadily

The FX-series indicator maps voltage thresholds to percentage brackets — it does not measure coulombs directly. A new replacement cell has a slightly different discharge curve shape than an aged OEM cell, so the camera can mis-map the first few discharge cycles and display sudden drops between brackets. This is not a fault with the cell. Run two full charge-discharge cycles through the camera body and the indicator calibration will stabilise. After those cycles, the displayed percentage should track actual charge state without large jumps.