Originally Posted by slvoid
It's actually not the mystery circuit on the housing. I'm powering the LED directly,
That's what I'm talking about - without knowing what that circuit does we don't know how it behaves under BATTERY power in normal operation.
If you connect a power supply directly across an LED then OF COURSE it's going to eat a lot of power if you overvoltage it.
You're operating the device out-of-spec.