Old alternator with new AGM?

[jamhass]

If its an internally regulated alternator, just install an external regulator that supports AGM batteries. Won't deal with the slow charging, but will match the charging voltage profiles and give you much more control.

[sailorboy1]

You guys are thinking the right or best answer, but it doesn't have to be that.

If it worked with the old batteries it will work with the new.