[Elecraft] K1 Battery Solution

[Brett Howard]

I'm looking for a good low weight small volume battery solution for using
with the K1.   I'd like to keep it outside the radio. I'll simply plug it
into the back of the radio to power it.  I'll probably put the same plug as
is in the radio onto a charger or just make some APP pigtails...

I'd like to be able to run the radio at full power so being able to get to
13+ volts would be great. I'd like charging to be fairly simple and safe.
I'd like the battery as well as the radio to fit into one of Rose's K2
cases... Another thing is that I would like a solution that will have decent
longevity if it's somewhat expensive. But if its a fairly inexpensive cell
then I'd put up with replacement every so often.   I'd like to be able to at
least get 4 hours at full power using "normal contest operating"
assumptions. I'll probably only use it casually so that should allow for
more like 7 to 8 total hours hopefully.

What solutions might you all recommend?  If you can provide links on where
the items might be purchased that would be greatly appreciated.

Thanks gentlemen

~Brett (N7MG)