Yeah, way back when I got my first digital camera (850K pixels at only $1100, ouch) I got some NiMH batts and a charger. That charger had a plastic cover because they got *real* hot when charging. The tiny microscopic little ?tits? that held the cover on broke off, of course, after a month so the charger lived out its life with scotch tape holding on the hinge side. My portable CD player packing son confiscated the charger and a dozen batteries and they have been MIA ever since.
I remember, in my first dig cam, normal Duracell?s would take only 10-15 pictures before the low batt light lit, no kidding. NiMH would run it much, much longer comparatively. I remember how amazed I was at how long. Interestingly enough the camera came with an AC adapter. Of course, if you used it the camera would lock up all the time and you had to do a hard boot to get it going again. Ah, the lovelyness of bleeding edge technology.
What really grinds my gears is 11 years later I just bought a 6MP Sony dig cam with 1Gb SD ProDuo card for $115 that obviously takes much better photos than my $1100 cam can ever hope too.
I just went to look at the Duracell input voltage, snickered at how light it was, then I - picked up the external power supply - to look at it. DOH!
I forgot about that!
So with the external supply considered they weigh about the same. Never the less, the Duracell does use a switcher as it is rated 120-240 as you suspected. The Energizer is rated at 120V.