lithium batteries wont last long in my browning black ice light, why?

Question

leds will still work but the zenon bulb wont

Answer 1

I don't know if you're saying they don't last as long as the manufacturer says they should or just that they don't last long, but: the xenon bulbs use a lot of power, about 5 watts compared to the LED's 1 watt. Lithium battery lifetime is given as 2 hours with xenon bulb. See the ref. for the specs.