I am aware that you must have a red light on the back of the car to run it. What would be better a light with a battery or one that i hook up to the car battery?

I like the idea of a battery because there is no needless wires, but then i have the problem of changing the battery + it adds weight.
On the other hand a wire is lighter and i can put a simple switch on it to control my light. Im leaning towards this. Can anyone think of a reason this would be a bad idea?

Also does anyone know a reliable cheap light? will a cheapo 2$ walmart one work, or should i get something special?


EDIT: I HAVE NO NEED FOR BREAK LIGHTS I AM TALKING ABOUT JUST A RUNNING LIGHT!

 

wouldn't the wire be as much weight as the battery, just get a bicycle light, with led's they take like one AA battery, and have 3 led's sounds like it would work to me.

 

I forgot to say, i cannot open my hatch anymore so i would have to climb back there to turn it on and off, or to exchange batteries. Also have a big roll cage to make that a throughly enjoyable job. I guess i could use wires and put the battery close to me but that defeats the purpose.