Power just went out in my area. I got an UPS to keep my internet on and enough flashlights to light up every single room in the house. That's the reason I like 18650 flashlights. Each area of my house has a 400 to 500 lumens LED flashlight running on 18650 with a couple hours of runtime. That's like keeping a 40W bulb on in every area. I have at least 2 more sets of batteries for each light, enough to keep my house lit up for another good 4 or 5 hours, which I don't need because is almost bed time. I remember the last time my neighbors kept thinking why I was the only one with electricity in the block until they realized I was on flashlights. Then they were surprised how bright these things were. 
cr123 size lights are good for carrying around but nothing beats 18650 when you have an extended power outage.
cr123 size lights are good for carrying around but nothing beats 18650 when you have an extended power outage.
