btw if you want dual head light (meaning turn on both low beam and high beam in the same time when the high beam is activate), then add a diode to bridge the connection on +/red wire from your high to low. Just something I want to add for projector light housing.

 

All your battery is is 12V. It powers everything in your car. So no matter what you hook your halos up to, its going to be hooked up to your battery. You CAN directly hook them up to the battery if you want, but it would be better just to splice into a 12V source like your lights so you can turn them on and off. You dont want them on 24/7. And halos do burn out sometimes. Iv had mine for a wile, never had a problem. If they do burn out, you can replace the L.e.ds. Theres a DIY on the internet.