What is the battery life on a DR optic assuming the hood is removed and the sight is set out where it will see night/ day  (IE always adjusting in a normal light situation.)

There are no published battery life figures.

Well my optima is on the original batt that went to afganistan with me the hood stayed off about 50% of the time I was there and its still working left in Jan so 8+ month and going strong!!!
      FREE

good to hear.

I am hoping for enough to withstand a 6month deployment without changing batteries with the hood off near 100% of the time. Unless it rains. Then the hood will probably go on.

The only problem with the design is that it requires removal for battery replacement after which it is highly unlikely that the sight will retain it's zero. And probably unlikely that I will have a chance to re-zero after removal.