The Stovebolt Site Forums The Shop Area The Electrical Bay Alternator change over questions

Just bought an alternator(1wire hookup) to "up-grade"from generator in 58 gmc270 6cyl.NO amp meter in truck.Do I just run a wire to battery&ground the alternator?What do I do with "old"gen wires?cap-off?What about regulator?Any mods there??

Thanks in advance

Yes. Run a 10 gauge wire to the post on the starter or a junction block. Use a piece of fuseable link in the circuit. you don't need the rest of the wires or reg. for this setup.

how would it charge the battery if i run a wire from alt to starter post?guess it backfeeds?wouldnt this "burnup"the starter?what about wires that went to gen?tape up out of the way?fused link for?


Clear as mud

fused link should be rated at what size between alt&starter post?Do I need to unhook all wires going to regulator?Should I remove regulator also?how would I check for correct charging?

Ground the alternator. run a 10wire to starter post.fuse size?Thats it?How would I check it?It should work just fine?just want to be sure-
CLEAR as mud to me now-

The alt. is naturally grounded when it is securly mounted. Make sure you have ground wires from the engine to the frame & frame to the body. Put a 2-3 in piece of fusible link wire between the battery connection & the 10 gauge wire going to the alt. You can buy fusible link made up with connectors on it. The diods in the alt. prevent curent from running back to it. The fuseable link will burn out if there is a short in the wire or a diode, or if you hook booster cables up backwards. You can check it with a voltmeter across the battery. It should go up to about 14 volts. On a one wire alt. you have to accelerate a little when you first start up to get it started.

Oh well grounded alt to frame.just was going to put an inline fuse-30amp.Is that too much?parts house didnt know about fusible link

In line fuse is no good. The alt. puts out about 65 amps. The fuse will blow very soon. I can't imagine a parts man not supplying a fuseable link. Have him look in the electrical wire catalog.

okay will go track one down

bought a 14gauge fusible link.Stated to use 2sizes smaller to protect set up.Not sure how 14gauge wire would hold better than a 30amp fuse?

What's the amp capacity of your alternator? If it's over 65 amps or so, the 14 gauge fusible link probably won't carry the charge current immediately after starting. I've seen alternators go to their full rated output for a few seconds after a heavy cranking load, 100 amps or more at times. The only function of a fuse, or a fusible link is to protect the wiring in case of a short, and prevent the wires from catching fire. I'd suggest a 10 or 12 gauge fuse link, and 8 or 10 gauge wire from the alternator to the battery cable at the starter, or even all the way back to the battery positive post. Put the fuse link as close to the battery as possible to protect as much of the wiring harness as you can. Be sure the fuse link/wire harness connection is a very low-resistance one, soldered if possible on both ends. You don't want any heat to develop at the fuse link hookup or it will melt the wire.
Jerry

63amp alternator.running #10wire to starter post.put #14fusible link in asdirected."use fusible link 2 sizes smaller than the wire used "
Nothing extra added to truck.just charging battery.but will ugrade headlights.

Ignore that advice. It's wrong. Either double up on the #14, or go to at least a #12. You'll burn out the #14 fuse link if tthe alternator ever goes to full output trying to recharge a very low battery. The battery, not the voltage regulator determines the maximum charge rate until the alternator stator reaches its current limit.
Jerry

okay will change to 12gauge fusible link.had to order online;this one horse town doesnt have anything higher than 14gauge fusible links

In ordinary use an alternator will not put out full current at idle unless the pulley size is very small, most are rated for 5,000 - 8,000rpm full output depending on the stator windings. One wire alternators generaly have high voltage low amp Wye wound stators to help them self energise. You likely would have been safe with the 14ga wire, worst case it would just fail.

14gauge is hookedup.No problems as of today.drove several times with lites&heater both on.No problems.Figure error on the safe side by putting 12gauge fusible link

btw, I was just in our Blue Streak wire and cable book today and it stated 4 sizes smaller for fuseable links. I had thought 2 sizes smaller would be acceptable though...

I read at several places about 2 sizes smaller.using 10gauge with 14gauge fusible.

Truck would not start tonight.Think I have a three wire set up.One wire runs to battery.2nd wire goes to terminal on back marked batt.THIRD wire is to go to an "indicator lamp"which my truck does NOT have.Should I run a hot from the ignition switch?

If you want a lamp run a wire from ign to the lamp. Run the ground to the alternator terminal. Lamps do come in handy. If you sling a belt a light comes on before you overheat the engine.

think i will tap onto the wire coming from the ignition going to the starter.