I used an LED drop-in and D battery adapters for AA Tenergy rechargeables.
I am now "prepped" as they say with a truly camouflaged flashlight with a much longer battery life.
You are innovative - drink 10 more bottles of Schlitz and you can light up your house. You could drink more and make flashlights to give to family for Christmas but you'd better let someone else do the cutting of the Christmas wrap paper.