Billy Lee wrote:
By your reckoning, my original F707 Battery from July '02,
recharged once a week, should be good for another 4 years?
Er... an NP-FM50 battery more than 4 years old? I'd make sure I have at least one "newer" spare battery when on a shoot! Expect a battery to last 2 - 5 years, depending on several factors.
Even though the cells have a finite number of re/charge cycles, they also have a time limit to their life. That life is determined in part by storage and operating temperatures, how often the battery is used, how deeply the battery is discharged each time it is used, how it is recharge (pulsed or steady current, etc.), whether it has been dropped (shock damage), and the natural chemical deterioration inside the cells.
A few months ago, I got some NP-FM50 "equivalent" batteries from Overstock.com for about $25 IIRC. They seem to be working well, and are claimed to have a higher mAH rating than the Sony battery.
Jim B. :> )