Originally Posted by dgpretzel
Might you please say what batteries you use in your DR-680? Powerex or Sanyo 2700's, perhaps?
I use Powerex and have run tests with all 6 ch p48. Only get about 2.5 hours.
Built an external battery sled of two sets of 8 Powerex in parallel and got 3.5.
Now using a DVD L-ion 9v 5400mAh and got 7 hrs, 6 ch p48.
Another user uses Eneloops successfully, but only as backup internals.
My external power cables are all "hot-swappable" (parrallel) connected so I can increase time if needed. (Also allows for two EQUAL power sources to be connected simultaneously-extending time)
Be VERY careful about external batteries. Significant numbers of users have fried their 680's by going over 12V. (Tekkeon 3450 comes to mind).
Some cheapo import batteries produce low-level noise; haven't had that with the DVD battery mentioned above.
When I use external battery sources, I still load the internals. The 680 switches to them seamlessly.
TMI, but hope it helps,