You can take the car to an autoparts store, like Autozone where they can test your battery and your alternator to see if they are working properly. They do these tests for free.
If your battery cables are worn out, get new ones.
Your battery starts the car (powers the starter motor) and the alternator takes over from there, recharging the battery as you drive and powering everything else. If the engine is shut off, the battery provides the power.
If your alternator is bad, everything will run off of the battery until it runs down.
Check your battery cables - they should be clean and nice and tight on the battery. There may be a date code on the battery - a letter and a number. The letter is the month of manufacture (A=Jan, B=Feb, etc.) and the number is the last digit of the year of manufacture. So G9 would be July of 2009. If your battery is 5 years old or older, it could be your problem. If your car has over 100,000 miles and the alternator has not been replaced, that may be the problem. (Replacing either one is a basic shade-tree project on most cars.)
Tony has it. Chris and Motorhead obviously know NOTHING about how engines work.
The battery powers ALL the electrics in the car and is kept at charge by the alternator.
Not a good idea.
First of all, if you have a corroded or loose wire, you can ruin the alternator, battery, and maybe even start a fire. The battery alone will only last about an hour at night. During the day you could probably get 2 or 3 hours out of it, but the fuel pump draws a lot.
Just put a voltmeter across the battery and see if you are getting more than 14 volts when the engine reved slightly. If not, then you have a problem and should not drive it.
Clean battery terminals, check connections at alternator, good belt, engine ground, etc.
battery
and your battery is charged by your alternator
Does the power for the lights come from the battery or alternator? I am having an electrical problem and think my battery is not charging because of a short in the system or bad cables but I need the car tonight if I think the headlights may stay on for 2 hours of driving.
