Fire means warmth, light, cooked food and protection, so knowing how to provide it for yourself in all circumstances is important information. There are not many experiences more miserable than having a camp site rained out, or getting to the beach for the barbecue and finding that you were wrong about someone else bringing the matches. If there’s a working car nearby, or you’re willing to do without your portable device for a few minutes, you can have fire long before you’re cold and hungry.
Clear away a flat spot on the ground and create a dirt base. Encircle this hearth with large rocks to act as a block against fire getting out of control. Build the base for the larger fire in the center of this protected area, either by layering tinder or by standing them up so they meet in a point, like a tee pee frame. Insert kindling material in strategic places in and around the base, and on top where you can reach it later.
Clean off the terminals (contact points) on the batteries to ensure a good, clean touch with the wire.
Straighten the piece of wire, and if it’s long enough, then re-twist the middle into a coil. Steel wool can also be wrapped into the twist to create a larger hot surface.
Position yourself so that the battery and the wire are close to the kindling, to avoid losing heat in the middle of the process. Place each end of the wire to opposite ends of the battery and hold them on tightly, but allow the coil in the middle to touch the kindling. Keep the wires in place until the coil is hot enough to light a fire. Don't forget to wear protective gloves in case the wire gets too hot for you to hold.
TL;DR (Too Long; Didn't Read)
You can use any type of batteries, even AA batteries, to light a fire.
Adding just a drop of lighter fluid to the kindling can be a big help.
Use common sense, especially if you’re in a wooded or heavily-grassed area.