Capacitors are frowned upon by almost everyone here. Do some searching and you'll find many questions related to yours. You'll learn about alternators, batteries, wiring, voltage, resistance, etc.
Educate yourself some, then ask a more specific question if you need.
Best wishes //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif