First, Thanks for having this forum and letting me on it.
The PTN04050C - Boost DC-DC Converter, may be just what I have been looking for.
I really like the "Puck" NIMH Mods.
I have been looking for something that would stabilize the output.
The sweet spot on a 4 battery puck is right around 5 volts.
This converter should work just fine.
I will let ya know as I go along
Lonnie