generator to alternator

well i finally did it, converted from my old generator to a one wire 100 amp alternator. what a huge difference. now at an idle i still get 14.87 volts, even with my lights, electric fan and heater on. wish id done it a lot sooner. friend told me the old generators only put out around 30 amps. it was putting out 15.50 volts but when switching the fan, and or lights, on it would drop to just above 12 volts. any way thought id share this, im really pleased with the out come.

 

Be careful if you have an ammeter. The 100A alternator can supply way more power than factory ammeters can handle. A voltmeter is much safer IMO, with no need to put the high-current path under the dash.

 

didnt even think of that, seeing as i have a voltmeter. but your right, the stock amp gauge would probably only go to 60 amps. kinda of figure id of noticed that and wondered if it would hurt anything, even not i would of had of gotten a gauge that went to the amps of the alternator, but no need with a volt gauge.

 

I have been thinking of doing the same. Could I ask what alternator did you buy? Where did you get it? Would any one wire alternator work? How about the pulley size? Thanks in advance.

 

Read up on one-wire vs 3-wire units! Here's a good starting point:
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

I'm in the process of converting mine using a 12SI unit (3-wire). I don't think the pulley size is that critical. All the 12SI units I looked at had the same pulley. 12SI alternators with a 94 amp rating seem to be a good choice.

 

I did this last year and I'm really pleased as well.
There was one thing though... that is I bought a alternator mounting bracket from a jeep place in AZ. It worked great, but the top bar that connects from the water pump bolt to the alternator, and has the sliding adjustment hole in it, was too light weight. with mine it seemed to vibrate when the engine was running and eventually started to fail... crack! If you have one of these, please check it often or replace it. I ended up getting a heavier piece of angle iron and fabricating it so that it would replace the thinner metal upper bracket. It is now rock solid. Just FYI.

 

I too have done this and glad I did so. I got mine free from a friend's demo derby Caddy. Unfortunately it is the big case but then again it was free. I also had to fab mounts.

Ken

 

im also thinking about making a thicker top adjusting strap for the alternator. the one i bought was off ebay, about 10 years ago, i think its a gm style. i also ran a heavy duty wire directly to the battery. so far so good. its nice to be able to turn my electric compressor and fan on at the time time and hear them both running at top speed. picked up three different size belts to get the right fit, then took the extras back. as for pully size, well it the stock pulley that came with it. i dont think oyu have to worry about the pulley size unless your going to turn a lot of rpm. my chevy 3/4 ton run about 2800 rpm on the highway and ive never had any problems with its alternator.