need help wiring dual alternator setup

[jeff_macon]

alternators are installed, just need a little help wiring em up. i have a 95 and 250 amp alternator. wanted to use the 95 amp for normal electrical needs and 250 amp to charge a pair of agm batteries i have in back for my audio setup. no one else, at all, has been able to help me, they're all up on chevy and that doesn't help me. the 95 amp alt is hooked up and charging fine but the 250 amp isn't charging. i have the yellow wire on the 3 wire pigtail connected to the yellow wire on the original harness so both alts are sharing that yellow wire, also have power wire from back of 250 amp alt going to batteries in the back but it isn't charging. i had only the 250 amp alt on before and it was charging at 14.6 volts. does anyone else have any experiance with this?? what wires should i have connected to the 2nd alt to allow it to charge my agm batteries? thanks for any help and advise...

 

[miesk5]

yo,

See if you can make sense of this;

Dual for On-Board Welder Installation in a 90Source: by flamedfordbronco

One excerpt; "...The wiring is actually really simple, you need to run a hot wire off of the battery to the number 1 terminal on the alternator. This gives you power to the rotor, so you want to run a switch on it so you can leave it off until you want to weld. Then, you run your welding leads; the hot (+) lead goes off of the positive terminal on the alternator, and you can run the ground to the case of the alternator. In this picture white is the positive lead, black is the ground, and the red wire is the hot wire from the battery..."



This is the 96 Alt Wiring Diagram; same as your yr

Note that Fusible Link J (12 gauge, Gray from Battery Via starter relay terminal (large post on right) to Alternator)

 

[jeff_macon]

yo,

See if you can make sense of this;

Dual for On-Board Welder Installation in a 90Source: by flamedfordbronco

One excerpt; "...The wiring is actually really simple, you need to run a hot wire off of the battery to the number 1 terminal on the alternator. This gives you power to the rotor, so you want to run a switch on it so you can leave it off until you want to weld. Then, you run your welding leads; the hot (+) lead goes off of the positive terminal on the alternator, and you can run the ground to the case of the alternator. In this picture white is the positive lead, black is the ground, and the red wire is the hot wire from the battery..."

View attachment 11650

This is the 96 Alt Wiring Diagram; same as your yr

Note that Fusible Link J (12 gauge, Gray from Battery Via starter relay terminal (large post on right) to Alternator)

looking at the diagram gave me a headache man..lol..i'm not good at all when it comes to reading diagrams of electrical ckts but i really appreciate it, you're the only one that has stepped up in a week..i'm going to go off of where you say to run which wires to where and see how it turns out..now, this is running each alt independently from each other right? i have a pair of 3g ford alts each with their own 3 wire pigtail harness to plug into the external regulators screwed to the back of the alt casing. on the pigtail, the white wire goes from the pigtail and just loops around to the small ground plug into the side of the casing..what about the yellow and green/red wires? i'll get a few pics to help out

 

[jeff_macon]

i contacted the guy from that dual alternator install thread. i don't intend on welding with my truck battery and alternators but he could def provide some helpful info..thx for the link sir

 

[miesk5]

yo,

good!

I know you don't need the duals for welding, the basic set-up and wiring is for any purpose incl charging those AGMs for your audio and the switch is good for you as well.