Converter 8-40V to 12V 20A
US $49.99
Specifications:
Input Voltage Range: 8V-40V DC
Output Voltage: DC12V 20A
Output Rated Power: 240W
Efficiency: 97% (half load); 95% (full load)
Ripple: 200mVp
Line Regulation: ±0.2%
Load Regulation: ±0.2%
Voltage Accuracy: ±1.5%
Enclosures: IP68
Case Operating Temperature: -40~85°C
Weight: 389g

ADDED:

Under "No-Load" conditions, the proposed Alternator can easily blast past ~40-Volts.
Then Smoke .............

As LQC noted, and I mentioned, the output voltage of an open circuit or light loaded permanent magnet alternator can generate damaging voltages (sometimes even enough to damage the winding insulation) so a series type voltage regulator or DC-DC converter will not work.

Yes, you both are absolutely right.
Converter does not solve overvoltage problem.

 

Under "No-Load" conditions, the proposed Alternator can easily blast past ~40-Volts.
Then Smoke .............
.
.
.

 

Converter 8-40V to 12V 20A

As LQC noted, and I mentioned, the output voltage of an open circuit or light loaded permanent magnet alternator can generate damaging voltages (sometimes even enough to damage the winding insulation) so a series type voltage regulator or DC-DC converter will not work.

 

Thank you for the reply.

I will be the first to admit that my cheap, Chinese alternator from Amazon might be the problem. It is a "one wire" alternator.
This is the alternator: Amazon.com: New Alternator Replacement For Mini 1 wire install with Volt Set Only 5.5 Pounds 35 AMP 1002111660, 1002111660, AND0525, 40052062 : Automotive

I went with the "Mini" alternator because of its smaller size and lower output of 35 AMPS. I don't know if it matters but the way I have it installed it is rotating "clockwise". It did not arrive with any paperwork or spec sheet.

At the moment I have the buggy disassembled for painting and the engine and alternator are not installed. But, I do have photos of when I was mocking it up for installation. Here is a photo of how it is installed in the buggy. Since this photo was taken I have installed a bracket from the top hole of the alternator to the buggy frame. (Don't be confused by that large, black cable to the lower left of the alternator. That is a rear brake cable that is running below the alternator).


Here is a photo of the buggy.


The battery is located inside that ammo box. I have a #8 wire running from the battery + post to the starter solenoid and a #8 wire running from the battery + post to the alternator output terminal.

When the engine is running and I attach the alternator wire to the battery it reads 14.7v.

Thanks for any help you can provide.