Figuring out compatability with rechargeable cells on some of these types of lights can be difficult... here's some ideas:
1. AW sells a 14670 that would certainly fit- but I'm not sure what type of regulation, or lack of regulation the light has... so it might be reasonably bright still, or may be much dimmer, depends on various factors....
2. If someone with one of these lights, who also owned a bench power supply could do a few experiments, then we could find out for sure. The trick is to start around 3V, and slowly ramp up the voltage and see what happens. If it contains a proper buck regulator, then the current should reach a peak somewhere around 3.7-4.5V give or take, and then start tapering down as 6V is reached, if it continues to taper downward up to ~8V, then it can probably handle the rechargeable cells just fine, if it continues to ramp upwards steadily above 6V, or there is no current "peak" in that 3.7-4.5V range, then the light is probably not compatible with a pair of 3.7V cells. Disclaimer: even if the current does continue to fall as the voltage is increase above the 6V mark, there is no guarantee that the electronics can handle higher voltage, it may fry at some point during the trek to test the higher voltage input, anyone conducting such tests would need to be ready to accept the potential loss.
Until someone does a test like this, or is willing to test the current consumption with some higher input voltages compared to standard input voltages, then there will really be no definitive answer... alternatively, we could email inova and see if they would be willing to divulge some information, but most of these big name companies have no interest in opening themselves up to that type of liability.
Eric
