Update: I exchanged the above mentioned lith poly bat for a Powerex 9.6v bat. I checked it out of the box and checked it with the multi meter, it showed 10.1v. This past Sat night I took it out for a trial run (The Gourds) but not before putting a fresh charge on it (registered 10.2v). The total recording time with opener was 2:42:21. Checked again after getting home, 10.1v. Guess that problem is solved.