The Stovebolt Site Forums The Shop Area The Electrical Bay Much smoke converting to 12 volts...need help!

This weekend I tried converting my '53 Chevy 3100 to 12 volts and nearly started a fire. I used the kit from National Chevy Assoc and thought I followed the directions. When I connected the new battery smoke billowed from under the dash and the hood. The 10 gauge red wire running to the ammeter nearly melted under the dash. It also melted down on the firewall where I had connected it to a 10 gauge wire running to my new alternator. Also the large wire running from my starter across and through the firewall melted. What did I do wrong?

You short circuited something to ground.

you'd hafta determine what you did wrong, we can't see it, but you must have tied a hot wire straight to ground, maybe you had the alternator connections wrong .... and when you connected the last battery cable you should have seen a fat spark and immediately removed the cable to prevent melting things

Bill

Repair the melted wires. Put an Ohm meter on the hot battery cable to ground. Disconnect stuff one thing at a time. When the Ohm meter reads open you have found the problem wire. Do not hook up the battery until it is fixed.

The 6V truck was positive ground. The 12V alternator is most likely negative ground. Which way did you connect the battery?

positive ground was a GMC thing, not Chevy

Bill

Get rid of the ammeter,and run a voltmeter! I kept my stock ammeter (dis-connected),just for looks,but installed a voltmeter under the dash,to monitor my circuits. An ammeter cannot support the extra voltage from an alternator! They're wired in series,with no fusible link,and they can over-heat very quickly. I installed a kit from A.A.W.,and on almost every installation page,there was a warning on this subject. Hope this helps.

Ammeters have been run with alternators for millions of miles. I have run my Suburban over 20,000 miles that way and no telling how many put on it before I bought it.

Also, of course people who sell voltmeters will tell you you need one. Do you expect them to say you don't need this but we'll sell you one anyway?

I don't know very much about electricity, but whatever you do, you need to stop letting the smoke out of the wires. Once the smoke gets out, you can't put it back in. Hope that helps!
Carl

Thanks. I'll go back and check again - this time more carefully! I appreciate everyone's comments.

Here's a link to some before and after photos and maybe you guys can help spot the problem.

https://www.dropbox.com/sh/ei6zsl2r3mmizwl/AABV3unqttq4BgThD8MtXhvpa?dl=0

In the before picture you see the red 10 gauge wires attached to the B terminal of the voltage regulator. Per the instructions, I removed the regulator and connected these wires to the 10/32 stud on the back of my alternator with a 10 gauge wire.

In the first after burned wire pic you see that I attached those wires to the firewall. Did this ground the circuit? See how the wire to the ammeter fried. Also to the left, see the wire that runs to my starter also fried. In the other "after" pic, you see where that wire attaches to the starter.

Thanks again for any help you can provide. Obviously, I'm a dunce and am paying the price...

Denny,

You need to start over and get better diagrams and instructions!

From what I see in pic #2 you have all the hot leads from batt/alt DEAD shorted to
the sheet metal on the firewall! Either your interpretation of the instructions is off OR,
what ever kit you got is dead wrong!

If you are converting to 12V I'd go with an internally regulated GM alternator. Get that old regulator out of the chassis.
Also, for simplicity's sake,
eliminate that AMP meter in the dash at least until you better understand EVERY wire and what its purpose is. You can always connect it again down the road if you really think you need it in a modernized charging system.

Here's a link to a PDF manual for rewiring a GM truck from Painless Products.
I'm pointing you to it because it is very educational!
They put LOTS of instructional information in them and you should LOOK AT PAGE 32 in particular; and compare it to your instructions.

This page is a BASIC engine compartment wiring set up for 12V GM style alternator. (and protects the wiring with a MAXI 50 AMP fuse under the hood (instead of a fusible link)
This basic set up is what I use to wire up
a new project to get the engine cranking,running,charging correctly before
continuing on with wiring the rest of the vehicle.

Go to Radio Shack and get a cheap $15 Volt/Ohm meter and familiarize yourself with the basic operations of continuity testing and voltage measurement. Get a good quality volt meter for the truck and wire it into the system whether or not you decide to keep the AMP gauge down the road or not.

Keep us informed and you'll get this sorted out! Good luck!
mike
http://www.painlessperformance.com/Manuals/10203.pdf

yes, those wires at the regulator should have been joined together and taped up, NOT attached to anything, especially body sheet metal - and that's 100% of your problem, replace the fried wires, tape up that junction and try again

also, you can discard that condenser on the coil bracket, it's a radio noise suppressor and even if you have a radio, it'll be useless - hopefully the white wire from the ignition resistor doesn't go to it

Bill

Thanks for the link, Mike. I definitely need "wiring 101" and this is a great start.

This forum is saving my butt!

Mike, your advice was very helpful. I read that manual as well as another book on 12 volt systems and feel more confident now. I replaced the burnt wires and now the truck runs fine, converted to 12 volt. I do want to add a 50 amp maxi fuse but my wiring layout is different than in the Painless Products example. The only fuse box that my 53 chevy 3100 has is for tail and stop lights. A link to the wiring diagram for a '54 is below - it's identical. I think the Maxi fuse should go on the 10 gauge wire between the starter and the ammeter, isn't that correct? Thanks again for your help.

https://www.dropbox.com/s/c5pjp89p8lh3uyj/54%20Chevy%20wiring%20diagram.jpg?dl=0

That is where I'd put it.

Sorry I'm late…..

Congrats on getting her running!
Yes, agree with you & cletis. I'd use NEW 10 gauge wire if you're inserting a 50 AMP Maxi in that line. You can get a holder and fuse that will mount in a convenient location so you can visually inspect it in the future. Then in the future you can also power stuff safely from that point using it as a distribution point.
As long as you're at it …. go here for more wisdom on electrical matters….. This guy is great!

http://www.madelectrical.com/index.shtml

He's saved a lot of our butts over the years! He guided me on a delicate modification to a 76 Rolls Royce that had a burned up alternator and regulator. $1500 for a new Alternator
and $250 for a new regulator!! (They were beautiful castings, but $1750
for delivering 12 volts was out of my league!)
He helped me understand how to keep the Rolls Royce idiot light, but converted to an internally regulated Chevy alternator from NAPA for $69; plus it had a lifetime warranty at the time! Problem solved.
mike

Will do. That 10 gauge wire is one of the new ones I installed so this should work out fine. Thanks, Mike and Cletis, for your help!

Didn't chevy use a positive ground on some 6v stuff back in the day?

no, GMC did

Bill

Thanks for those couple links Mike. Good sources.

When I wired my truck, I used a small amp battery charger to test the system, before hooking up a battery to it and having a melt down in case I messed up.

Brian