I had this problem in the past, and only later found that the battery ground wasn't good. Removed black battery cable from the grounding point (opposite end of cable from battery), cleaned the spot where it was attached, and cleaned the cable end, then reattached it. Worked fine then. Only one possibility though.
The alternator or a poor wiring connection.
If the battery and alternator are good and the charging system is not working, then you either have loose or corroded wiring or the drive belt is slipping.
bad wiring harnest
This could also be alternator problems as in a bad diode in the alternator.
Yes, because a bad coil will not allow the engine to run. But if the engine is running then the coil has nothing to do with the alternator charging the battery.
Check the Battery and cables and if it's not that it could be the alternator.
When the light is on it means the system is not charging. This is almost always the alternator. Can also be a loose alternator belt, loose wire, or break in the wiring. Drive the car to an Auto Parts store and have them check the charging system. You can also check the voltage output of the alternator with a multi-meter. At the battery posts with the engine running it should read between 13.5-15 volts.
An auto battery could be leaking for a couple of reasons. The alternator could be overcharging the battery causing the leakage. Or the battery itself could have a short or other internal problem causing it to leak when charging.
The computer controls the alternator. If the charging system is malfunctioning, that could be the cause of the weak battery.The computer controls the alternator. If the charging system is malfunctioning, that could be the cause of the weak battery.
You could have a bad battery, or you might find that your alternator is not charging. You can almost always get a local shop to put the meter on both battery and alternator to check the charging system.
your alternator ain't charging your battery or a bad connection draining the battery
Could be charging system (battery, alternator) or fuel system (pump, line).