Many of our old alternators are insufficient in the amp department to run all of the modern gadgets (fans,FI,Pumps,amps...ect) along with the other normal electrical accessories without discharging the battery some.

My question is about a set up on a 67 Dodge that had most of the aforementioned items. The owner had the normal charging system intact but with a 100 amp alternator. In addition, he also ran a large auxiliary wire directly to the battery to charge it (from the alt). He said the alternator only puts out current only when there is demand and the stock charging system charges when there is a small need but when there is a larger need the system uses the path of least resistance (large wire from alt to bat) and charges the battery.

He said he has used an amp meter to check the amp draw of all of his electrical accessories and the charge to the battery. He claims to have several thousand miles on this setup and has not experienced any voltage or overcharging problems. His EE friend felt this set up was ok as well.

What do you guys think?

If the wiring from the battery and alternator to the loads are adequate then I would say it's a fine setup. The large wire from the alternator output to the battery acts as a shunt so that much less current flows through the original ammeter and associated wiring. This is a good things as the ammeter and wiring are marginal for a 60 amp alternator let alone a 100 amp alternator.

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Joshua