HERE IS THE BEST SOLUTION

Try using hearing aid batteries. Most likely either size 312 or 13. I use
(3) size 312 batteries in my Trophy Ridge sight. Hearing aid batteries are a zinc-air battery. That is, they actually begin to discharge as soon as you remove the tab but work great. Best part - they are readily available at any drug store, Walmart or Miracle-Ear Center but they don't last but a month or so. So for $8 you got a seasons worth.