Hope things go better with your second unit. The battery does not require a lot of pressure to make good electrical contact. Don't compress the battery spring more than 1/2 way regardless if you are using a short or long battery cap. Noalox on the battery tube and battery cap threads will eliminate problems like this too. Clean the threads with a soft cloth dampened in alcohol before applying Noalox. The other thing to look for is a wet or loose 510/eGo connector. These should be cleaned and dried daily with Kleenex.
Thank you very much for the input. I have not as yet made it to Home Depot or Lowes and remembered to get some noalox even though I do plan to. Did however try cleaning the threads with qtip and iso earlier in the week. Didn't note any significant difference in performance though. I'm using Panny NCR18650PF batteries that are less than a week old. They are fine batteries BTW.
The return of my first Zmax was due primarily to paranoia. Things that act up during my "shake down" period are not well thought of and not often forgiven. My thinking is things that don't perform well initially don't get better with age.
On over tightening the battery tube, This is my first telescoping mod. So, I really am kind of guessing what is too tight. What I do is tighten the extension tube until I no longer feel the tube move while in use (thread slop). So to swear that I am not overtightening would potentially be BS (too early in the day to start lying). If you have a technique you could share I'm open to giving it a try. I'd definitely perfer not to trash my Zmax due to rookie mistakes.