Using a voltmeter, you can check the charge of your car battery. If the battery is fully charged, it should be around 12.6 volts with no load.
If the reading is below 12.45 volts, it’s a sign that your battery needs to be recharged, or replaced.
Disclaimer: Every car battery is different. Without actually examining the car, it can be hard to figure out exactly what’s actually going on with the battery. If you’re having trouble with yours, you’ll get the best advice from a professional. And always get it looked at as soon as possible, so that small problems don’t get the chance to grow into bigger ones. Never drive your car unless you’re certain it’s safe to do so.