The circuits are somewhat robust, but the maximum voltage is listed on each PCB (and in the sale description). The 3V battery drainers are capable of using 1.5V to 3V cells, handle "dead" cells almost as well as the 1.5V VoltVamp, but stop producing light a bit earlier. The 1.5V VoltVamp can take a cell below 0.6V with diminished brightness. They are what I typically use for power outages and a nightlight for hotel stays.I'm a little late to the party it seems.
What is the max input voltage? Wouldn't want it to go *poof* on the first try.