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I spent many years working with pumped up car alternators for big car audio systems. One thing to consider is that as you add windings and bump up the output amperage, you change the output curve of the alternator. Standard car alternators produce good amperage at the lower end of their rpm range to handle stop and go driving. The high output alternators we used (120A and dual output 120A) shifted the charging curve way up the rpm scale. These alternators were designed for semi's and vehicles that spent most of their time at highway speeds. We had guys that only drove their rides in town and mainly on the Saturday cruise and ended up with dead batteries by the end of the night. The alternators also produce a lot more electromotive drag. What was happening was that below 50mph, the oversize alternators output was considerably less than stock. We tried overdriving the alts with smaller pulleys and it was much better. To do this, the alt must have needle bearings instead of simple bushings to handle the higher rpm. We had one little Mazda truck that produced enough alternator drag at idle with the stereo cranked up, that it lugged and killed the engine.
Basically, the idea here is that a higher output alternator run at the same rpm as stock may actually output LESS during around town riding. Unless the alt rpm is boosted, there might be less available for proper turnsignal function and such while idleing at a light.
Basically, the idea here is that a higher output alternator run at the same rpm as stock may actually output LESS during around town riding. Unless the alt rpm is boosted, there might be less available for proper turnsignal function and such while idleing at a light.
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