In the right corner it's....Sir Gawain! He is nephew to King Arthur, and an honorable knight of Arthur's Round Table. He is very popular with the ladies, and quite charming. He is loyal to his king and queen and keeps his promises.
To charge the battery, the alternator voltage output has to exceed a minimum charging voltage. This minimum charging voltage is 13.8 volts dc across the battery terminals, or at the output of the alternator. A single lead-acid cell starts to charge at anything over 2.25 volts.ince a 12 volt battery has six cells, any 12 volt lead-acid battery needs at least 13.8 volts to start to charge. This voltage will be enough to fully charge or maintain the battery on a trickle charge, but charging time will be very long at 13.8 volts.
If your alternator has a lot of power to charge, don't give it any resistance by installing too small of a charging wire. Run at least an 8 AWG wire from the alternator to the battery. Go bigger, (lower AWG number) like 6- or 4- AWG if your battery is in the trunk.