Schottky diode alternator

[Daox]

Are there any modifications (besides rewinding) you know of to get higher charging voltages at lower rpms?

[gumby79]

Regear/reduce the od of the pulley. Im considering this on my Dodge, any one now of a cross reference for pulley od. and shaft size. As at idle the fild won't excit, to slow with a/c cluch and blower motor on hi.

[gumby79]

https://alternatorparts.com/alternator-pulley-size.html

Yes, you can increase your alternators overall output as well as increase power output at engine idle speeds.
Check the size of the pulley on your alternator. If you are having problems with overall alternator output or charging at engine idle, maybe a smaller pulley is all you need. The most common pulleys on GM, Ford and Daimlier/Chrysler vehicles are the 6-groove 2-7/16, 2-3/8 and 2-1/4 inch pulleys, by reducing the pulley size to 2" or 1-7/8" your alternator will start producing power sooner and produce more power cruising down the boulevard or on the highway. Also, because your alternator is spinning faster the fan will move more cooling air through the alternator adding to component life, to little air flow can burn up an alternator.

?Will this help ?
?What is the point of loss due to over speed?
Oil Pan ?what do you anticipate the %gain in efficiency to be?

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Watch out for voltage drop causing a bad voltage signal from the relocated battery . Dodge used to small a gage wire for there remote voltage regulator on the fire wall in there pick ups, result the lights flicker/pulse voltage gage bounces .

[oil pan 4]

Originally Posted by Daox

Are there any modifications (besides rewinding) you know of to get higher charging voltages at lower rpms?

Start with a wye wound stator. Looks like the cut in voltage is as low as 1,000 to 1,200 alternator rpm where delta cut in voltage is around 2,000rpm.
Other ways to get more voltage at lower rpm would be to swap in a lower resistance rotor, or boost the voltage going to the rotor.

[serialk11r]

So as of 2021, it seems like a 50A active diode costs around 20 bucks shipped from Alibaba, and you would need 12 of them for an alternator, which is pretty expensive (not to mention they are bulky).

As an alternative, I found this: https://www.vishay.com/docs/93804/vs-175bqg030hf4.pdf

0.5V drop is respectable, and the package is compact so you can screw 6 of them onto an aluminum heatsink and hang it off the side of the alternator. 30V max reverse voltage may or may not be a problem, I'm not sure. Maybe some zener diodes to absorb voltage spikes would be a good call.