GoPro Hero3 Ultimate Timelapse Battery Saving Hack

For my underwater time lapse adventure i want to be able to take a lot of pictures with the least amount of battery usage as possible. So i got a a few herobus connectors and hooked up an arduino pro mini and a LDR, seams to work, will be nice to try it under water... I got the hero bus connectors from, chargeconverter.com/