COlineman78
WKR
I can't fathom anyone burning through two 18650 batteries on one hunt. How long do you plan on staying out? Do you use you lamp on the high setting all the time? I can easily get through a 7 day hunt on one 18650 with plenty to spare in my zebralight. I've always carried a spare just in case I end up butchering or hauling an elk out in the dark but so far I've never even come close to needing the 2nd battery. I've always got a Petzl E+lite in my bino harness as a backup as well.
There is a very large variation in the quality of 18650 batteries. I have some of the cheap ones that barely last 6 hours and some expensive ones that last the entire trip. Both have the same mAh rating. Also, some are designed for high amperage devices and some are better for slow draw. Look up your flashlight and how you plan to use it and then compare the discharge curves for some batteries at that amperage. There are a ton of sites out there that test and post the discharge curves of 18650s.