I have found the Canon powershot G12 to be an excellent performer for time lapse.
Canon states the G12 is capable of approx 370 shots and 1000 with the display off what it doesn’t mention is whether the flash or auto focus is used. So it can be assumed that with these switched off the battery life will be considerably more. So I decided to test the battery to see what it could do.
With the battery freshly charged I took 1338 shots with the following settings.
white balance manual
Aperture priority F4.6
0.6″ shutter speed
ISO 80 manual
At an interval of 3 seconds. Note the interval was set at 2 seconds but turned out to be 3 seconds when timed.
The battery was still showing full. So i continued shooting until the battery dropped to 2/3rds amassing another 680 images, totalling 2018 shots and 1/3rd of the power used .
The images were taken in RAW format approx 10MB each which are 4 times bigger than JPEGs. Totalling 20GB.
Note the image size can vary as I have previously taken some RAW images that were 14MB (not sure why this happens).
I took another timelapse with another charged battery. Everything was set to manual but this time used Jpeg format and had a shutter speed of 1/60th sec and shot until the batteries went flat. The end result was 5112 shots which was pretty pleasing.
I looked into trying to extend this to get more shots, by closing the display which theoretical should drain less power. Sadly due to software limitations it switches the auto focus back on, which is just not practical for timelapse. So it looks like I’ll have to settle for around 5000 shots.
I also discovered you can add a mains adapter if needed so you can shoot until your card is full. With the largest card currently available (128GB SDXC) and plugged into the mains you could take approx 112,000 10MB images (448,000 JPEGs). Some DSLRs shutters are not even rated for that many. There is a lack of shutter life expectancy information on compact cameras, but the general consensus seems to be they have a greater life expectancy than DSLRs due to less working parts.
The G12 can also take the Eye Fi card which will send the images to your Wi Fi network, this is new technology and it is unclear to me whether this can be done whilst continuing to take images. If you can do this then you could theoretically take unlimited images.