Battery sized standby light.

Ever since i saw the glotube, i liked part of that concept, but didnt really like the implementation. Well today i couldn’t stop thinking about a better implementation. Basically i want something that glows continuously at resonable brightness unless it reaches the cutoff voltage, and then i want to be able to put it in a standard 18650 charger to recharge it. Right now, im thinking 16340, or 14500 as the cell inside it.

Will post more when i start building a prototype

How about one of these little fellas?