My bike needs to be running at about 2500-3000 rpms for the battery to be charging. What RPM does a car need to maintain in order to charge the battery? If I left it at idle, will the battery charge or do I have to drive it? Also, how long does it need to be driven/idled? Dumb question I know, and I got mixed answers when I searched. Thanks!
Look at your gauge in the car. If it's above 12, then it's charging the battery. If it's right at 12, then it's not doing anything, if it's below 12 then it's draining the battery.
I agree with Eagle. Every car I've ever owned will charge the battery at an idle. You can let it idle for 20 or 25 minutes, or drive it around for like 10-15 minutes to allow the alternator enough time to put a charge into the battery.