Depends upon how the battery was discharged, but generally yes, once a lead acid battery has been fully discharged from leaving lights on or similar methods which drain the battery slowly it will never recover. The only time this is not true is when the battery is drained from the starter motor due to the vehicle not starting for some other reason. In this case the battery will recharge without any long term damage provided the recharge is done within around 24-48 hours.
No, a bad coil will not drain the battery.
Bad battery or a parasitic drain
No
Yes
No.
no
Yes. If the alternator is dead and you drive the vehicle, all the power is coming from the battery and it will eventually drain completely. Also, if a diode is shorted inside the alternator, that can drain a battery.
Waiting for the battery to drain completely to extend battery life.
yes
You have a bad cell in the battery and a bad cell will drain the other cells. get another battery
When the alternator goes bad or goes out completely, the car's battery will be drained. I suggest you pull the alternator and have it tested. If the alternator is bad, you will most likely need a new battery as well. The cost is around $200.00.
YES!My version:A bad relay switch that goes bad can "stick" in the on position and leave what ever it powers on and drain the battery You should be able to see the item that is on.