RangerRick

I had my alt rebuilt to 165 amp. I saw it tested on the bench and it ran off all his gauges. I installed on jeep, 11.5 to 12 volts at idle. Take it off go back and same thing,it works there, but not on Cherokee.
I rewired all wires to 6 gauge from alt. to battery relay to the new hvy duty battery. Several grounds cleaned, upgraded in wire size. Nothing working yet. I bumped up RPM, in gear to 1000 rpm and it goes to 13.4 volts, with out a load.
I installed a Tarus fan and just run the high side. I can't do idle, the jeep has to be running 1300+rpm to keep the battery charged. I get the same readings with my meter leads at the battery while driving.
I am sure when I go back to the shop it will read good again. I wonder if the elec bench motor spins at 3000+rpm and that is the reason it looks good there with no load on it.

Any ideas where to look, or change something. I did the same upgrade to my chevy truck and it has a tarus fan and all is well.

Best Regards, RangerRick

Cj8722

I have the same prob with my 96. It has a 160 amp and I upgraded all the wire to 0awg wire. I caint figure out why at idle it won't go above 12.4 volts. And the batt is brand new only a week old

RangerRick

It went back to the shop and we checked the alt on the vehicle and off. It worked off, but not as well on. We left the wiring as it was with the upgrades and then ran a jumper 10 gauge from alt to Battery. It worked. At least I got 13.4 at idle, with the tarus fan running. We both think the main relay has an issue. I will replace tonight. If I find that does the trick,I will PM you to let you know. I will also remove the direct run 10 gauge wire from alt to battery that the shop added and change to a 6 gauge.
Good luck with yours, RangerRick

Cj8722

Thanks man let me no how that relay works out for u

Gee oh Dee

Clean all grounds and contacts.

I bet that will help.

RangerRick

I did that in the first topic. If you have any other ideas, let me know.
Todate, all wires new and upgraded to 6 gauge. New battery and cables, main relay and of course alternator.
On the bench 3 times it works great, my thought is he uses an electric motor to spin up the alternator and it may be 3400 rpm motor.
While driving, from 1500RPM up it does fine, 13.4 volts.
At idle 1000 RPM, in gear it is 11.+ volts. Out of gear it idles at 1200RPM and is 12.4 volts.
Which way do I go to speed up the alt RPM. Smaller/Larger pulley?

Best Regards,RangerRick

PingPong

YOu have a rig that is 23 yrs old.... wires and relays might look good, but I am willing to bet they are brittle and have bad conductivity. Also most alt are rated for max amps at a certain voltage... not at idle. That is why you see the premier power welders come with a hand throttle

RangerRick

I guess you missed the first few threads I wrote on this issue.
Everything is brand new. The wires + and -, relays, battery and the alt, so those are not the issue.
The hand throttle is a new idea. When the shop spins up my alt and puts it under load the elec motor they use to spin the alt is a 3400 rpm.
I will look into a hand throttle like we have on our firetrucks.
Thanks for the idea,RR

PingPong

SO you are saying you put a whole new wiring harness in your rig? You can have voltage drop anywhere in the system, not just in that circuit that can affect your alts performance. AND yes I read your whole Post.

Agent_Oragnge

RR, FYI sarcasism and respect for senior members will get you the info you want faster. chain of command son. just my .02

Gee oh Dee

Keep it on topic folks.

If ANYONE has a problem with ANYONE you can do one of two things.

PM the person or report the issue/post.

Any other actions are unnecessary and unwelcome.

No matter who you are, what you know, or how long you've been here, everyone gets treated with equal respect.

RangerRick

Thank you sir. I did not expect this thread to go this way.I'm good with it.
Ping Pong/Agent Orange, Thank you for the PM's. Apology is accepted.
Best Regards,RangerRick