I'm amazed how few CPFers have embraced PowerGenix nickel-zinc (NiZn) AA cells. Nickel-metal-hydride (NiMH) AAs were popular, in part, because they delivered a voltage under load that was similar to that of alkalines. Now that L91 lithium AAs have become our favorite AA primary cell, doesn't it make sense to interchange them with a rechargeable AA that is better-matched? Lithium and NiZn share the same voltage under load, the same high performance in low temperatures, and similar resistance. Why not cut ties with 1.2V to 1.5V legacy chemistries and enjoy the new standard voltage: 1.6V?