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Old Feb 27, 2003, 12:31 PM   #11
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Originally Posted by steve6
The number of bats is not a measure of capacity only the voltage used by the camera. The capacity remains the same - the amount in the individual cell.

A torch which uses 2 D cells will last as long as one with 4 D cells. The 4 job is just brighter.
You're missing a few things...in a flashlight the load (lamp) is a dumb device, it just direct connects to the batteries without any circuitry so the light gets whatever voltage the batteries are delivering. Digital cameras are different. The following is based on my knowledge of PDAs and how memory cards react with them:

There are two relevant measurements, voltage and milliamp hours (mAh). Voltage is the power a battery can deliver. mAh is the time that power can be delivered.

Memory cards are massive loads to batteries. You may experience low voltage conditions with brand new alkaline batteries because they do not respond to power surges as well as Lithium, Nicad, and NiMH batteries. What works for you may not work for your friend.

Voltage is like horsepower in an engine. Consider a 4-cylinder 110 HP car and a 230 HP truck pulling a heavy boat and trailer. While both do reasonably well on level ground, the small car labors when it comes to a hill. Both vehicles must exert the same force to pull the trailer up the hill at the same speed, but one has a better capacity for doing so. The same applies for batteries. A 4.8v source (4 rechargeable batteries) is better able to deliver power to memory cards than the 2.4v source (2 rechargeable batteries) because most cards require either 3.3v or 5v (depending on the card). Both sources must first convert amps into a higher voltage but the 2.4v source works harder and burns out sooner under these conditions:

watt-hours = voltage x mAh / 1000

Compare 9.6 watt-hours for 4 2000mAh AA vs. 4.8 watt-hours for 2 2000mAh AAs.

If you start out with more voltage, you'll have more watts-hours available for a device of the same load, and although the cameras will have different conversion circuitry for the different battery sources, you still have similar loads in the 2AA and 4AA cameras, an LCD, CCD, memory card, and the support circuitry. And that's why I said it was a balancing act...less voltage does mean less shots in the end.
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Old Feb 27, 2003, 1:04 PM   #12
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most cards require either 3.3v or 5v (depending on the card). Both sources must first convert amps into a higher voltage but the 2.4v source works harder and burns out sooner under these conditions:
Good point, you've shot me down in flames.

However, my friend's Fuji 2AA camera (2600 I think) seems to last as long as mine.

Ok, I'm not comparing like with like but his camera lasts all day taking plenty of pics.
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