I took 5 different lithium ion proprietary batteries for the Panasonic FZ series cameras and measured how long they last.
I used a Radio Shack digital voltmeter with an RS-232 serial connection to my PC as the measuring device:
I found some opensource code on the net that will drive this voltmeter from linux and then hacked it to work with FreeBSD, which is what I use at home. I was able to save data in 10 second intervals, in a very simple ASCII file format, saving data samples of (time, volts), like this:
000000 08.300 000010 08.300 000020 08.300 000030 08.300 000040 08.300 000050 08.300 000060 08.190 000070 08.170 000080 08.160 000090 08.150 000100 08.140 000110 08.130 000120 08.120 000130 08.120 000140 08.110 000150 08.110 000160 08.100 000170 08.100 000180 08.090
I connected the battery to a hacked-up charger cradle:
and some jumper wires to connect from the voltmeter and the cradle to the camera, itself:
1. Turn camera off, turn voltmeter on, insert battery in cradle.
2. Start the computer voltage-reading capture.
3. Let the computer sample a few values before you turn the camera on.
4. Turn the camera on and let it 'idle' with power-saver disabled
5. Let it run until the camera turns off due to the battery running out.
6. Stop the computer capture and create a .jpg from the data
These are actual measurement runs done with computer-collected voltage measurements at 10 second intervals.