I just read this- http://taperssection.com/index.php?topic=157574.0

Re: A 9V Battery is NOT!
« Reply #6 on: August 14, 2012, 01:54:54 PM »
FWIW the Powerex rechargable 9V batteries have a nominal voltage of 9.6 but when new, fully charged and without load are between 10.5 and 11.5V. The Nbox doesn't seem to work well with the rechargable 8.4V but does great with alkaline or these Powerex ones. So if anyone needs a batter in the shape of a 9V and needs more than 8.4, it might be worth trying the Powerex.

EDIT: Branding is Powerex, not sure why I was thinking Maha.
EDIT: I just checked again and they are Maha Powerex. I give up. :P
« Last Edit: August 14, 2012, 01:58:03 PM by johnw »