NP-50 vs NP-50A batteries for Fuji 660EXR vs 550EXR

Started May 15, 2012 | Discussions thread
Billx08 Forum Pro • Posts: 11,373
Re: NP-50 and NP-50A batteries all same same

aniramca wrote:

Thanks for the reply. One of the reason that I just got an F660EXR (another Fuji camera) is for my daughter who plan to use it while traveling. I have 2 NP-50 batteries for my X10, and therefore I can lend one to her.

I was afraid that for different battery voltages used in the old film cameras, it could "fry" the camera.

There's nothing to worry about with the different NP-50 batteries. I suspect that the 3.7v and 3.6v rated batteries are substantially the same. Below is a chart showing the voltage discharge curves for several types of rechargeable batteries. The Li-Ion battery curve is the topmost, and you can see that from fully charged to flat, the voltage varies from about 4.0 to 3.0 volts. During most of the time that it's used, it will be delivering from about 3.8 to 3.4 volts. If the camera's voltage checking circuit was designed to power the camera down 3.5 volts, it would be wasting 20% of the battery's capacity. Shutting down at 3.4 volts will allow the camera to use about 90% of the capacity. It's not safe to go below that or you'd risk losing or corruption data on memory cards, because at the end, the voltage can plunge very rapidly, unlike alkaline batteries whose voltages drop continuously at a pretty steady rate. The URL for the small PDF document the chart came from is listed below. FWIW, "SLA" stands for Sealed Lead Acid and "RAM" for Rechargeable Alkaline-Manganese.

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