It means that you have an alternator fitted. An alternator needs an amount of battery voltage to generate electricity. A generator/dynamo will make voltage without a battery being present.
No.
No, you can charge it in the car fully connected.
The problem is probably the alternator. If the alternator fails to keep the battery charged the battery will keep the car running until it can no longer supply voltage to essential systems and the car will stall.
Why do you want to unhook your battery??? If the alternator is good the car will continue to run, if it dies then you have a bad alternator this is why you would want to unhook the battery cable to check and see if you have a bad alternator
disconnect the negative (black) first then positive (red).
You probably have a failing alternator.
Unhook the car battery.
Yes, it can happen.
AC runs on the battery. If the car is off and you run the AC, then start the car, it will stall.
You can either pull the fuse or unhook the car battery.
Just hook up the charger to the battery while it is still in the car and do not unhook it.
Scan tool or unhook the batteryScan tool or unhook the battery