What's the generally preferred external battery option for the 680 these days?
My stash of old 9V "DVD" LiIOn batteries are growing unreliable and I think it's time to move to something else.
I still use 2 old powerrunners that keep on ticking, and a mountain of various Tekkeon and Tekkeon knockoffs. For a while they were available on eBay at great prices, but I think that ship has sailed. I like the knockoffs better than the actual Tekkeons. Personally always go with 12 volts and in addition (try to remember to) keep fresh batteries in the deck just in case...
I think there are some good options in Amazon, but generally not inexpensive. Others can comment with their own personal experience, because these are the only 2 battery types I have ever used on anything requiring more than 5V.