I have run this test twice and got the same results with 5 minutes of each other
Just recently got a tascam dr680 with a couple naztech pb15000 batteries. Last night I ran a test to get the life time of the battery.
Specs of test:
4 channels, 2 stereo tracks
1+2 channels bsc1-Littlebox-680 line in mode
3+4 Motorola droid razr- xlr line in mode
Backlight of 680 was on always
Battery on 9v setting
24/48
Total run time 13hrs 25 minutes
This was pretty impressive, enough for a day at a festival most likely, especially if you have some aa in the battery tray.
I will try to do a test with 6 channels going, maybe tonight... If anyone wants me to do some tests with other setting or functions on ill do my best to do so.
I hope this is helpful.