Can a battery be so dead the alternator wont charge it?
A) Alternators are designed to maintain a battery's charge, not to recharge a dead battery. Charging a dead battery with an alternator will result in premature alternator failure. via
What will happen if the alternator is not producing power?
If you were to try and start your vehicle without an alternator, the battery alone would not be able to produce enough power to get the engine running. Even if you had a new car battery and were lucky enough to turn the engine over, it would probably run for about 10 minutes before the power cuts out. via
Can a bad battery cause alternator to have low voltage?
To bring it all together, when a car has a weak battery that battery will want lots of current. The current demand of the battery lowers the system voltage so the voltage regulator compensates by sending more current through the rotor. At idle, the alternator is incapable of making the needed current. via
How do you test a alternator regulator? (video)
Can a bad battery destroy an alternator?
A weak battery cannot have any effect on alternator, but a poor or weak alternator can deteriorate the battery very quickly. A broken battery also has an effect on an alternator as it puts more pressure and stress on the alternator while working and sometimes destroy the alternator as well. via
How do you check alternator output? (video)