Originally Posted by IronSpinnaker
The wrong battery can cook your alt. You need to use the battery that is specified for your boat. The battery has a certain resistance to charge and the Alternator and regulator is matched to that. Wrong battery can ruin your alternator or cause the battery to over charge and off gas.
While any dumb regulated alternator, with no internal temp compensation, can cook itself when attached to a large bank, where it will be asked to produce full output for hours on end, alts are not "matched" for a particular battery. Alternators are specified by amp output and voltage not by the battery they should be connected to.
If you have a large bank of flooded, AGM or GEL batteries they may over work and cook your alternator. However, that same alternator converted to external regulation with a temp sensor can run for years charging that same bank because it will run cooler being temp compensated...