No one seemed interested at all in September when I mentioned the Energizer Quick Switch flashlight in this post. But given what SwedishChef went through, sounds like they could have come in very handy. For those not familiar with the Quick Switch, it can use AA, C, or D size batteries just by adjusting something (I don't have one--sliding some stopper tab in the battery compartment, maybe?). Anyway, it's a self-contained way to use any batteries you would commonly find at the supermarket. Even if you have your own stash of batteries for your own lights, it might be very advantageous to have a couple of these Quick Switches to give to others.

The other idea I had along this line of thinking are battery adapters or "upsizers". They let you use AA's in products requiring C or D size batteries and cost a couple bucks each. Less, if you bought them in volume, I suppose. They are basically plastic shells, shaped like a C or D size battery, into which you can slip in a AA. So, if your supermarket runs out of D's for your flashlight, but has AA's, you can use upsizers with the AA's as substitutes. Obviously, a single AA holds a lot less energy than a big D, but at least you'll have power available.

One unique advantage of an upsizer is that you could put lithium AA's in a D-sized light for lighter weight, better cold weather performance, and/or better shelf life. Lithium D's do exist, but that's definitely an exotic item. Well, of course, you could also just buy a light that takes AA's in the first place, but then you lose the fun of talking about how to get lithiums in your D-cell light. <img src="/images/graemlins/grin.gif" alt="" />

Anyway, not perfect solutions or substitutes, but when you've got a D-cell light or radio and the only batteries available are AA's, seems like these will do in a pinch.