I'm actually kinda surprised that they won't supply much current because
I have an SLR 35mm camera that uses a lithium battery (2cr5). Besides
physical size, does anyone know what the big difference is that allows
it to output, what must amount to, several amps of current when it
recharges the flash?
The CR2016, according to Energizer's data sheet, is about 38 Ohms rising
offscale past 120 Ohms shortly after 70mAh of use. They point out that it can
be used in pulse applications and supply about 6.5mA.
Assume that 38 Ohms is fixed, independent of current being supplied (it's not,
it gets worse when you pull more), then if your LED needs 2V and the battery is
supplying a peak of about 2.9V (about right for most of its life) you will get
about 0.9V/38ohms or slightly less than 24mA. Which is about right for 2V on a
red LED (the old style red LED is about 1.55V+21*I, which in this case is about
2.05V at 24mA -- about 2V.)
I doubt the CR2016 would supply even that 24mA, though.
Now, if you look at the fatter CR2032, it's all the same. The spec shows about
38 ohms, again. They suggest a slightly higher pulse current as an example,
7.3mA, but the device is otherwise very similar except for its greater energy
storage.
None of these things deliver the energy very quickly.
The 2CR5 you mention is NOT a button battery. And it is designed to deliver a
20mA continuous current, an ability to actually provide 1.5A continuous, and
with peaks of up to 3.5A!! -- as compared to a button battery's design for about
0.1mA and ... maybe up to 0.5mA. That's quite a healthy difference. Notice
that the 2CR5 weighs some 38 grams as compared to about 2 grams for the button
batteries.
Comparing those two families is TOTALLY crazy-minded!!
Jon