Philips M-640 Compatible Battery SBC-5260C 6V 4200mAh

Philips M-640 / M-660 / M-670 — 6V Ni-MH Replacement Battery (SBC-5260C)

This is a 6V, 4200mAh Ni-MH replacement battery for the Philips M-640, M-660, and M-670 cameras. It matches the original cell's voltage and form factor, using part reference SBC-5260C. If your camera no longer powers on or drains quickly after charging, this cell replaces the depleted original.

• M-640, M-660, and M-670 platform: These three Philips camera models share the same battery bay dimensions, 6V voltage rail, and connector orientation. One cell covers all three without adapter or modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge using the OEM charger. The BMS accepted the cell cleanly on first insertion and held voltage across a full discharge sweep without dropout.
• First-cycle initialisation on Philips M-series bodies: Run the first charge entirely through the OEM charger or inside the camera body before shooting. Some Philips M-series bodies need one complete charge cycle from the camera itself before the battery-remaining indicator maps correctly to the new cell's discharge curve.

Why the Philips M-640 battery indicator reads full then drops to empty suddenly

Ni-MH cells have a flatter discharge curve than Li-ion. The M-640's battery indicator is calibrated against voltage thresholds, and a new Ni-MH cell holds voltage steady for most of its discharge cycle before dropping sharply at the end. The camera reads that flat mid-section as "full" and then hits the cutoff threshold quickly, making the indicator look like it jumped from full to empty. This is normal behaviour for Ni-MH chemistry — it does not indicate a faulty cell. After two or three full charge and discharge cycles, the camera's reading becomes more predictable.

Flash not recycling fully between shots after installing a new cell

The flash capacitor draws a high burst of current to recharge between shots. On a new, unconditioned Ni-MH cell, internal resistance is slightly higher before the first few cycles complete. This causes a brief voltage sag during capacitor recharge, which extends recycle time. Run two full charge and discharge cycles before judging flash performance. After conditioning, internal resistance drops and recycle speed returns to spec.