potentially
I could Return the tekkeon but I would still be in need for a 12v Li-Ion battery.
I can't imagine why if I am sure it's running at ON:Y 12v it would be an issue?
But what do I know
It's akin to playing with a loaded gun. Just because the safety is on doesn't mean you should point it at someone.
Good luck with the Tekkeon; I just think there are far too many options at an equivalent price point with zero potential of supplying more than 12v.
This is kinda where I'm at on this. However, if you're careful and diligent, then there's nothing to worry about.
That said, I know how I operate my gear. After some period of time, I get used to everything and maybe after time has passed, somewhat complacent or forgetful about checking battery setting if that's important. I know me (and Murphy's Law is constantly looking to screw me over) and at some point I'd forget to check that the Tekkeon is set to 12V and BAM, now I have an inoperable DR-680. Since that's one of the 'mission critical' pieces of gear and alot more costly than a new battery, I personally know with my habits, that's not a chance I'd be willing to take. Just me though.