Brand name batteries such as Energizer and Duracell make economic sense compared to cheapies according to a new article penned by physics professor Rhett Allain in Wired.
Allain found that cheap sells from the US Dollar Store, went for around US$0.20 each, around a third of the big brands. By hooking up the batteries to a simple circle and plotting power delivered, Allain discovered that the energy cost between all the batteries as almost identical.
That said, the voltage of cheap batteries dropped off very quickly indeed and they would need replacing three times as often as the more expensive cells. Combine that lack of convenience with the likelihood that the rapid loss of cell voltage might cause some electronics to die even faster, the results were a thumbs up for Energizer and Duracell overall.
Allain didn't look at rechargeable batteries which generally have a capacity around the same as Energizer and Duracell but obviously cost many times more.