The Stovebolt Site Forums The Shop Area The Electrical Bay switching to alt.

Thinking of switching from a gen to a alt on my 53. Wondering which to go with 1 wire or 3 wire. Right now it's a 12 sys with Hei and the only accessory is Radio and back up lights.. Any suggestions. Thanks.

I have a three wire. You should be able to find one at any auto parts store in case you break down on the road. Not all auto parts stores have the one wire one.

Most people characterize their alternators as one wire, when in fact they are three wire. The 10SI or 12SI are three wire alternators, but the 12SI is better because it self excites and still gives you three wire functionality. It also doesn't have a min RPM and starts charging the second it starts turning. I just have a 10SI. Be sure to get an alternator that is UNDER 50 Amps. If you don't, you run into the problem of shunting. That entire subject is covered here:

http://devestechnet.com/Home/Native12VUpgrade#gauges

Three wire is better because you have idiot light functionality. While that isn't a big deal in itself, there are things you can do with that functionality to expand other things.

The three wire alternators are internally regulated so there is nothing else to buy and act the same as one wire alternators in that it only takes one wire from the main terminal to hook it up to the truck. There is a second wire that is jumpered over on the Alt itself. The AC Delco Part Number is 13-4010 for the standard 42 Amp version.

I like to go with the 1 wire, no external regulator no idiot light and I change the ammeter to a volt meter so there is no big current running through the dashboard.

I have used a 1 wire, no external regulator, no idiot light, and I used the stock 1954 Ammeter (12V system). However, my alternator is probably 45amps.

I did not need/want any more wires.

It was installed around 1997 and is still working fine. It "excites" at around 800 RPM. When you start the truck, you normally go above 800 RPM. Once it is "excited" it charges at all RPM.

Ok, so i'm looking for a low amp alternator 42 amp. What car/truck would have had one so i can look it up.

Check the application data at the bottom of this page.

1973 C10 Pickup according to RockAuto.com

Part Number: REMY 20040 for the 42 amp one, which is the best one for the job really because it's below the 50 amp ceiling.
http://www.rockauto.com/en/moreinfo.php?pk=38314&cc=1029967&jsn=805

The NAPA part number is 13-4010.

Cletis's link shows only 63 amp or higher which isn't recommended unless you are bypassing your stock ammeter.

To hook it up, connect the Main Terminal to the Ammeter Main line to the (+) Battery. The two terminals that are to the side are 1R (closest to the main terminal) Charging Light, and 2F the one beside 1R is for jumping over to the main screw terminal. This is necessary for excitation. Just a 14 gauge jumper wire is all that's needed. Look at that link Cletis gave you though.. lots of good information there. The link to my website above shows how to wire it as well.

Local automotive electrical shop says he can get me a 1 wire 42 amp for 65.00. Is that reasonable.

Don't buy into the "under 50 amp" myth. In the words of Macbeth, it's "sound and fury, signifying nothing". A 65 amp unit will be available just about anywhere, at extremely reasonable prices. I've seen several on Ebay recently, priced under $50.00 with free shipping.
Jerry

I have the early externally regulated GM alternator on my Suburban with an ammeter. I don't know it's amperage output but it pegs my gauge on start up. I know of no ill effects of that. And I've never heard of an ammeter causing problems in real life. Only heard the myths on here.

The very serious issue is not a myth according to Powermaster and anyone else who understands the difference between vintage style ammeters and more modern ones. Just because a dead short doesn't happen every day, don't make the mistake of thinking it never happens. If the path of least resistance is under the dash, you will have a disaster of epic proportions on your hands. Hopefully the truck isn't in the garage when it happens. There isn't an alternator manufacturer out there that would recommend more than a 50 amp alternator for your maximum 50 amp gauge.

The problem comes in when people do not realize that manufacturers design their alternators with RISK FACTOR calculated very carefully. Spend the time on the phone with these Alt manufacturers like I have, and you won't be dismissing everyone else's safety so quickly. Well, YOU would, but everyone already knows that.

just because an alternator is rated 65 amp instead of 42 amp does not mean it always puts out 65 amps! That is the MAX, if your battery is in good shape, you will almost never put out that much unless you leave your lights on for an extended period or something like that. It is safest to not max out any of your gauges though.

During normal operation, it should never put out max amperage. But this isn't about normal operation. There is no way Chevy would put a 50 amp alternator or higher in your stock truck due to the risk factor issue. It wouldn't cross their minds.

The maximum amperage that 50 amp maximum rated ammeter can stand without starting to glow is 50 amps. With the extra amperage having nowhere else to go, and it has to go somewhere, it will take the path of least resistance... perhaps a weak wire, or weak connection. It's just idiotic to sluff such a danger off as alarmist or something. Especially when precautions are out there and the solutions are very easy to deploy. Read the article on my website. I didn't say it because I was bored. Like everything else, it was very carefully written with experts from Powermaster on the phone making sure that everything is absolute irrefutable fact. There are other websites that talk about this issue too. Don't take my word for it, do your own research.

Here is my question. Let's say one somehow pushes too much amperage through a stock ammeter. Wouldn't the ammeter just blow like a fuse, killing all power to everything attached downstream of it?
Carl

But after how much damage to whatever else is connected to it? But not like a fuse. There is no shunt on a stock ammeter, so it would burn through its 50 amp rated material. More like a wire that got too much amperage. This takes time, so it would be VERY hard on any other part of the system. The only time it could happen is if there was a dead short somewhere that cause the alternator to think it needs to put out max amperage. Admittedly, hardly ever. Its the Hardly I am talking about. There just isn't any need to go there. All of the solutions are listed on the site. A simple fusible link, fuse, circuit breaker, etc solves it short term. Best to remove the vintage ammeter and go with a voltmeter.

I do appreciate everyones info but fact is I don't know why i would ever need a 65 amp alt. The truck already has everything i'll ever put on it and the 35 amp generator handles it just fine. I Just wanted to up grade to a alt and a 42 amp is an upgrade. Now weather or not the ammeter will handle more i don't know but from what i've read here it will handle a 42 amp alt. I Did find some on napa's site for 50 bucks

If you want to learn more about the tech involved in all of this, a great primer is here:

http://www.madelectrical.com/electrical-tech.shtml

There is an article on that menu page that discusses the bad idea of the vintage full flow amp gauges. They don't make amp gauges like they did in the 50s and 60s anymore. Good luck and I think you have the right idea!

Ok, What's the trick to getting ahold of Madelectrical.

Phone number at the top of the linked page: (559) 539-7128

I tried several times awhile back and nobody answered. Not sure how active they are anymore. The best information about Alternators and Vintage Ammeters I found was the engineers at PowerMaster.

Actually got through to him. Very knowledgeable. Bought the kit for the alternator. Called the parts store today and found a 63 amp alternator for 43 bucks and lifetime warranty. Amazon has a nice volt meter and tach. This should keep me busy for the weekend.

I think you will be very happy switching to the Alternator. The internal regulation means no more worrying about regulators, and the battery will stay charged more efficiently. If you need help with any hookup, just let us know.

Thanks, i'm sure i'll have a question or 2