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1G Saturn alternator and still having voltage issues ..

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awdmonster1904

15+ Year Contributor
788
387
Aug 23, 2007
Chino, California
How's it going dsmtuners


I've been having issues with my voltage dropping for quite a while.
Here is my set up

Saturn alternator with a self exiting regulator 125 amps
Optima battery (new) relocated to the rear all wiring is 2gauge
Including the power wire coming from the alternator
Moroso battery switch
Not really a daily driver ...

Here is it's behavior when it worked

14.4v idle driving
13.7 fans on
13.0 lights on and fans

Now it's been idling and only at 13.3 I find it hard to believe that a Saturn alt with 125 amps and 2 gauge wire would be at this voltage on a new battery

Just recently i had an issue where the wire was 8 gauge to 2 gauge power wire from the alternator and it was getting hot so I replaced for 2 gauge my mistake
When I replaced the wire everything was working I let the car sit for one day
And now it had worst voltage than if I were to run a stock dsm alternator

I'm really confused I need some tips in how to approach this issue where to start
 
Is the alternator new?
Is it relocated?

When I did my swap I bought one from advance. And with the o2 housing being there so hot it actually messed the alt up(like 3 days)
I returned it for a new one and put some heat duct aheild on it and hadn't had a problem.
Sometimes you will get a bad new alt/starter etc from those stores....
 
How is your battery grounded? Grounding to the body in the trunk could cause low voltage. Are you running a sense wire? If so, where did you run it. A buddy of mine is having the same issue, not sure what's causing it.
 
G'day.
Try a heavy gauge earth wire from the alternator to the block and check your earth wire from the battery. You should have bare metal under the earth wire fitting, tighten up the nut and blot/screw then spray with a galvanising paint.
Cheers
Ross
 
I'll start by checking my grounds and see where it takes me
I have the battery grounded to the car but I never checked it it was A good enough ground[DOUBLEPOST=1411469963][/DOUBLEPOST]
How is your battery grounded? Grounding to the body in the trunk could cause low voltage. Are you running a sense wire? If so, where did you run it. A buddy of mine is having the same issue, not sure what's causing it.

Since my battery is in the rear I have the ground to the car chassis and from the engine bay I have another ground wire going from the bay to the inside of the car I'll start by making sure that the grounds are good[DOUBLEPOST=1411470122][/DOUBLEPOST]I also did some research on the wire that a half it's the aluminum copper coated wire which in my not be very ideal for high amperage
I might have to swap all the wiring out in favor for welding cable but until I get back into town I'm going to first start by checking my grounds and go from there
 
Last edited:
I'll start by checking my grounds and see where it takes me
I have the battery grounded to the car but I never checked it it was A good enough ground[DOUBLEPOST=1411469963][/DOUBLEPOST]

Since my battery is in the rear I have the ground to the car chassis and from the engine bay I have another ground wire going from the bay to the inside of the car I'll start by making sure that the grounds are good[DOUBLEPOST=1411470122][/DOUBLEPOST]I also did some research on the wire that a half it's the aluminum copper coated wire which in my not be very ideal for high amperage
I might have to swap all the wiring out in favor for welding cable but until I get back into town I'm going to first start by checking my grounds and go from there

Just a thought...when you put the jays kit on, did you sand the anodizing off the bracket that bolts to the block? Adding a ground wire from the alternator like thirsty said may help if not. The anodizing prevents good contact.
 
I thought I would post what I recommended to you here for reference, the problem I see is that your alternator charge wire runs all the way to the battery then all the way back up to a positive post when you have all your high amp draw ( fuel pumps, fans, ect...) so your alternator is working extra hard trying to push a lot of power a very long distance and your battery is absorbing way to many amps which is probably what killed your Odyssey battery (causing it to swell) was over charging. so by putting a fused distribution between your alternator and battery and running your fuel pumps and fans off that I think you will solve your volt problems and wont over charge any more battery's. and if you still have some issues i would go with larger and better quality wire after that. also make sure your relay trigger wires for your fuel pumps and fans remains on the batter side so when you turn off your cut off switch they turn off immediately.
 
I thought I would post what I recommended to you here for reference, the problem I see is that your alternator charge wire runs all the way to the battery then all the way back up to a positive post when you have all your high amp draw ( fuel pumps, fans, ect...) so your alternator is working extra hard trying to push a lot of power a very long distance and your battery is absorbing way to many amps which is probably what killed your Odyssey battery (causing it to swell) was over charging. so by putting a fused distribution between your alternator and battery and running your fuel pumps and fans off that I think you will solve your volt problems and wont over charge any more battery's. and if you still have some issues i would go with larger and better quality wire after that. also make sure your relay trigger wires for your fuel pumps and fans remains on the batter side so when you turn off your cut off switch they turn off immediately.

I'm not sure of his plans, but if he wants to run on a real track, they won't allow your method of wiring. The alternator must run back to a cut off switch, and the battery is run to the same lug of the switch. Another cable is run from the other side of the switch to power the car. This way, the engine dies if the switch is cut off.

A good majority of people running at the track are wired this way without issue. Most of the current flows through the cutoff and back up to the front of the car, not through battery. To keep it safe, running a fuse close to the alternator, and another close to the battery is a good idea.
 
Welding wire: Great idea.
Sense wire: Hooked to fans or the fuel pump, NEVER to a regulated 12v source.
I think its the sense wire personally. If its hooked up to the battery you might as well hook it straight to the alternator. There's not that much resistance in the run from the bay to the back to induce an adequate V drop. When the sense wire sees a decent drop it will kick up the output. Fuel pump is a great place to put it. That way you get good output at any temp or rpm/load condition vs the fans only dropping when they're actually running.
 
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