Flashlights are a basic item in any 72 hour kit. In an emergency you are going to need light: to set up a tent, to walk a trail, to find your stuff in a shelter, to read a map at night, etc etc. After doing a fair amount of research, I feel a kit needs three flashlights: a lightweight handheld battery powered flashlight, a battery powered headlight, and a crank or magnetic induction flashlight.
I made the decision to power all my electronics with Energizer Ultra Lithium AA batteries. Using AA batteries really narrows which flashlights you can get. Big flashlights with D batteries are way too big and heavy for an emergency kit. Small flashlights with AAA batteries would require carrying AAA batteries and AA batteries. My solution was to buy whatever cheap flashlight I could find at Walmart that took AA batteries. For me it was a Black & Decker Cliplight. It is about 6 inches long, takes two AA batteries, and is reasonably bright at night. I plan on keeping two Ultra Lithium batteries in it, and packing two spare batteries in my bag.
A headlight makes it easy to see while setting up a tent in the dark. It can also be handy if you are carrying a toddler while walking on a dark path. My choice of AA batteries again limited my options here. I ended up getting the Rayovac SE1WHLT-B Sportsman Xtreme on Amazon. It takes a single AA battery and claims to provide 45 lumens. It also has red LEDs so you can get a little light without ruining your night vision, and a low-power blue LED that allegedly makes it easy to see blood in the dark (designed for hunters), but I’ll probably just use it to save battery power.
The downside to this headlight is that it won’t last long on a single battery. With the main light, it will probably only last around 3 hours. Because of this I’ll be packing two spare batteries.
It is vital to have light even if the batteries die and you run out of spares. This means you need something you can power on your own. The typical options for this are hand crank lights or magnetic induction lights (the kind you shake). I personally hate the shake lights, and my radio of choice comes with a crank and a flashlight, so I think I’m set.
If I end up with a little extra room in my pack then I’ll probably pack several flashlights that I consider disposable. These are cheap (or more often free) LED flashlights from Harbor Freight. I consider them disposable because they tend to take button cells (like the common CR2032) and I’m committed to carrying only a single type of battery. The flashlights themselves are so inexpensive that it wouldn’t bother me to lose one (or two or three), trade them away, or to just toss them when the batteries die. If I end up putting these in my packs then I’ll probably use them up before draining the batteries on my primary lights.