Battery becoming very hot

Reading Your Ammeter
The ammeter shows current to or from the battery, not including power to the starter.

• It should show small steady discharge when starting.
• It should show 15-20 amps charging at most after starting, quickly dropping to 5 amps or less.
• After a few minutes of driving, the ammeter should show zero current.

If it ever pegs discharge, there is a dangerous short. Do not drive. Shut off all switched power. If the short is on an 'always hot' circuit, the fusible link will melt.

If it charges high due to discharged battery, try low rpms to reduce alternator power, turning on headlight and fan to divert some of the current from over charging the battery. Stop and allow battery (and wires) to cool off if charging rate does not come down. Use a slow charger if possible.

Understanding Charging Systems with Ammeter: