The 6V 12ah battery will blow the 12V with 6V (or 9V) regulators away (I'm at 2 mths+ with only a 6V external, no internals, and the G camera is still reporting 99%)...now I'm sure every regulator has a different efficiency, but I have yet to find anything close to a straight 6V battery (tried 3 different styles of regulators). All of my external regulator tests with a 12V 12ah battery have made it around 45 days prior to the camera switching to internal D's. Unfortunately with only a 6V external, you loose some warning of low voltage on the daily reports since the camera will no longer switch to internals due to it actually "seeing/reporting" the 6V "external," as an "internal" battery on the report. Now with a 9V regulated external, you at least see it switch to internal D's and know you need to swap it soon. I guess with a straight 6V battery you could use the % count down on the daily status images or the "BL" data within the picture metadata as your notification, but I have yet to find that data very trustworthy and it isn't reported on the daily report. With a straight 6V battery you also loose your internals (or if you keep them, they just end up dead at the same time as the external) and really like having the internal D battery "buffer" prior to the camera locking up for "DEAD BATTERY" if I don't get too it in time. I wish I knew if we could feed straight 12V into the external port on the G-series? (I know its not recommended, but neither is 9V since the plug says 6V and that works just fine)! However, that would be the best of all worlds...the EXT/INT on the reports would work, the internal batteries would still be the buffer, the external batteries would have twice the capacity (12v-12ah vs 6v-12ah), and the inefficient regulator wouldn't be wasting the additional run-time! I'm totally guessing, but I'm pretty sure the G-cameras already have an internal regulator built in to neck the 9V external to 6V internal...I just wonder if it can handle the 13-14V of a freshly charged 12V external straight in and not fry???