Graetz SK60 6V Ni-MH Replacement Battery 4200mAh

Graetz SK60 / TMC4888AF — 6V Ni-MH Replacement Battery

This is a 6V, 4200mAh Ni-MH replacement battery for the Graetz SK60 and TMC4888AF film cameras. It restores power to light metering, autofocus, and flash systems when the original cell degrades. Dimensions are 88.95 × 47.55 × 36.50mm — measure your existing pack before fitting if you are unsure.

• SK60 and TMC4888AF compatibility: Both models share the same battery bay dimensions, voltage rail, and connector pinout, which is why one cell covers both. Either camera draws from the same 6V bus to run the meter, AF motor, and flash capacitor charging circuit.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge runs, monitoring voltage under metering load and flash recharge draw. The cell held a stable output across both low-draw metering and the higher burst current the flash capacitor pulls.
• First-cycle conditioning on Ni-MH camera packs: Ni-MH cells shipped in storage have a suppressed capacity until the first full charge completes inside the OEM charger or camera body. Run one complete charge before shooting — this lets the camera's battery-remaining indicator map correctly to the new cell's discharge curve.

Flash recycling slowing down before the battery indicator drops

The flash capacitor recharge circuit pulls a short but heavy current spike after each shot. As a Ni-MH cell ages or sits at the bottom of its charge curve, internal resistance rises and that spike causes a temporary voltage sag. The camera's meter may still read sufficient charge, but the capacitor takes longer to reach firing voltage. If recycling time between shots is stretching out noticeably, the cell is near end of useful discharge — recharge before continuing to shoot.

Battery percentage jumping erratically on the camera display

Ni-MH cells have a flatter discharge curve than lithium chemistries, and most camera firmware maps battery percentage to voltage thresholds tuned for the original factory cell. A replacement cell with slightly different discharge characteristics can cause the indicator to skip or drop suddenly rather than drain smoothly. This is a firmware mapping mismatch, not a cell fault. Run two full charge-discharge cycles and the indicator typically stabilises as the camera's BMS learns the new cell's curve — check that the resting voltage at full charge reads 6V before drawing any conclusions.