Can I wire my car stereo directly to the battery?
Yes. Although it will drain the battery over time. If just for testing purposes, on aftermarket radio, hook the yellow and red wire to positive on battery, black to ground.
What gauge wire should I use for battery terminals?
Most car batteries use a 12-volt power supply, which is best suited to a 6-gauge battery cable (the standard).
What is the best battery terminal for cars?
The grease that should be applied is white lithium grease. It is readily available at automotive stores. It will not interfere with the electrical connection, but will help prevent future corrosion by displacing the air in the surrounding space.