Insane light output

I especially ordered for biking me this lamp. And when you turn on the (bright) madness. Even at the lowest level it reaches in the woods from most to see every little obstacle.
In addition, I want to use them more often while hiking, and there is a small problem, the battery can not really attach well to the head strap. Although I have now eliminated this "problem" by the suturing of the battery pockets on the head strap.
So at this price is a strong buy recommendation.
What given me some cause for concern is still relatively strong heating at the highest light level.
As soon as I can draw conclusions about the battery life, I'll add here.

Edit: The battery had at the beginning 2 of 3 LEDs, now the lamp runs in the lowest level for 3 hours. And yet still has a beautiful brightness.