[Elecraft] Why are the batteries internal to the KX3?

[hawley, charles j jr]

I don't like to disassemble the KX3 to take out the batteries when not using or to do battery maintenance.
I would rather have a slim case with the same rectangular outline as the KX3 that attaches to the rear panel and just plugs into the KX3 thru the external DC input.
Has anyone done that as an accessory product?

Chuck Hawley
 c-hawley at illinois.edu

 Amateur Radio, KE9UW
 aka Jack, BMW Motorcycles