Help with Voltage Light after alt upgrade (1 Viewer)

[yoda-g3]

I just got done with the project from hell. PHH, flush, hoses, belts, new radiator, the list goes on.... I decided to upgrade to a 130A Sequoia alt while I was at it. I got a local one with reasonable miles on it and took it to two places to have it bench tested and they claimed it was good. I also upgraded to a 2AWG charge cable while I was at it.

Finally got the rig fired up and the volt light is coming on. Main batt was trickled charged beforehand. (New dual Die Hard Platinum's).

With harness to alt unplugged I was reading 12.5v, with it plugged in I was getting 13.8. (So I know the alt was engaging.) It stayed right in the 13.7-13.82 range even with lights, heat, etc on. Revving made very little difference. Seems reasonable since my battery was full. Voltage also read the same at alt as well as batt posts.

What's crazy is that the rig ran and sounded better then it ever has. Lights were brighter and no volt meter twitches when bottoming the windows out.

I've just dumped over 20 hours into this thing and if I have to tear it all back apart again I might cry. (The joys of having a turbo setup is that everything takes twice as long....) I don't even know how I'm going to get that damn thing out again without pulling the shroud and radiator.

Any help would be great.

 

[BEE-JAY42]

I don't know if you're having the same issue that I was but it may help, I change from the old external regulator type alternator to a new 100Amp internal regulated type, my light would stay on until I revved the engine to 2500 rpm and then would go out and stay out. I fixed the problem by putting a higher wattage bulb in the warning light, might be worth a try.

 

[superjuice]

make sure all the alt. brackets bolts are tight. The alternator cage grounds thru the new bracket and bolts, any corrosion or such could impact the output. Sounds like your voltages are the same as mine though (I have the 150). At first startup i read 14.2, then drops to 13.8 usually within a few miles. I installled mine without removing anything, very tight but doable. What does the stock voltmeter show? perhaps you missed hooking up a wire from the am1 box? check the voltage from the alt + to alt cage. Then alt + to block, then alt + to neg batt terminal. then batt + to batt neg. then batt + to alt cage etc. All of these should be within a few tenths of a volt depending on whats running.

As I recall there are a few different ways to increase the wire gauge from the alt. I would try to tighten everything up, see if that helps. Check the voltage from the cigarette lighter as well, could be voltage drop from something. Try reverting back the the original wiring configuration but leave the new alternator in place. HTH, good luck!

 

[yoda-g3]

Thanks. I just drove it to work today and it stayed on the entire time. Battery rest voltage was 12.52 first thing this morning with the engine off.

Sounds like there might be a little hope here. I just REALLY don't want to swap this thing out again. I was planning on beefing up to a new 2AWG frame - block - battery ground.

I did run a new 2awg charge lead from the alt to fused post on the batt. I also attached the factory charge wire to the 'B' post as well, then just removed the small wire coming off the charge post in the LM1 box. I've attached a pic. (Seemed better then taping it.)

 

[Impreza]

Tangent question.

What voltage is too high to be concerning? I hit some giant puddles yesterday thanks to the rain storm and my SGII is telling me it is spiking all the way to 14.7 then somewhat goes back to the normal 14.2-14.5 (which still seems kind of high)

 

[rhyary]

Yoda,
You have to measure the voltage as it comes out of the alternator. Don't disconnect anything yet.

First, when u start in the morning your voltage should drop to between 8V to 10v depends on ambient temperature.

Than the alternator should be charging at 14.4 to 14.2. Duration depends, but right after morning start it should be doing it.

If you have a simple voltmeter, you need a simple helper. Have the helper start to vehicle while you measuring above.

Be systematic. If the voltage drop is not registered at the alternator the voltage register does not know to bring it up.

It that works at the alternator, you have the answer. If alt register 14.2 but it does not get to the battery post, you know it is in the cable.

If it gets to the battery but not to the small wire in the L box, than troubleshoot there.

Rami

 

[Photoman]

Can you double check where the regulator wires where pushed in to the new alternator connector with the picture in post #24 in the upgrade thread?
As rhyary and others said, it would be nice to see the charge voltage change more from start up. Try turning everything electrical on, then start the engine while watching the meter across the battery terminals. The alternator output should be higher (14+), then drop some.
If your meter has an AC setting check across the battery terminals with the engine running. Any voltage reading on the meter means one or more of the alternator diodes are weak or bad. HTH

Bill

 

[superjuice]

"If your meter has an AC setting check across the battery terminals with the engine running. Any voltage reading on the meter means one or more of the alternator diodes are weak or bad."

Thats plausible, never thought about that!!Photoman

Also, you should probably disconnect the aux. battery setup while doing these tests. not sure about your setup but it should be removed as a factor during troubeshooting. FYI I have Dual PM-1's controlled with a hellroaring unit. If you need any readings let me know. I have had trouble with my setup before

 

[yoda-g3]

EDIT: Forgot to add that I did quadruple check the pin out for the harness adapter. Looking from back with clip at 12:00 - Bottom left yellow / blue stripe; top left black with blue stripe, top right solid black.

Ok, first thing this morning:

(All measurements from battery terminals.)

- Rest voltage on the main batt = 12.68V

- Disconnected aux batt.

- Started rig. Voltage briefly dropped to 8-10V while cranking, as soon as she started it hit 14.22. (High beams on and heater on high.)

- Left idling for a few minutes and voltage settled at 14.16V.

- I set my multimeter to "2V AC", even without touching anything I was reading
.017. As soon as I touched the batt terminals it hovers from .003 - .004. When I remove them it jumps back up to .017.

- For kicks I took a high quality set of jumper cables to run a "beefed up ground" from batt to motor to frame then redid all the measurement with the same results.

- After 25 minute drive to work voltage read 13.55 while idling with lights on. The AC test showed the same .003 - .004.

Worth noting that the dash light stayed on during all of this.

Also worth noting that when I was trouble shooting this the first time the voltage from the alt 'B' post matched what I was reading at the batt.

 

[rhyary]

Yoda,
I get the same numbers.
Check my thread wondering why mine drop to 13.8 for a visit and go back up to 14.1. but not always.

 

[yoda-g3]

Yoda,
I get the same numbers.
Check my thread wondering why mine drop to 13.8 for a visit and go back up to 14.1. but not always.

Just checked it out. Interesting. One thing that bothers me is that even after driving around for well over an hour yesterday my Sears PM-1 batt was only at 80% charge this morning. That's the type of thing that will shorten its life pretty dramatically. Seems odd its not getting topped off fully. I currently have all aftermarket crap unhooked so I don't think its a phantom draw.

Makes me really want to get to the bottom of this.

(Chart for reference.)

 

[rhyary]

Can not see the chart

 

[yoda-g3]

Weird. It shows up in my browser.


Here's a link to where I got it. At the bottom.

Batteries - Measuring State of Charge - AltE

 

[rhyary]

Are you compensating for temperature?


7.Correct the readings to 80°F:
Add 0.004 to readings for every 10° above 80°F.
Subtract 0.004 for every 10° below 80°F.

Table of FA
Degrees 100% V
120 12.62
110 12.61
100 12.61
90 12.60
80 12.60
70 12.60
60 12.59
50 12.59
40 12.58
30 12.58
20 12.58
10 12.57
0 12.57


Table of AGP
Degrees 100% V
120 12.92
110 12.91
100 12.91
90 12.90
80 12.90
70 12.90
60 12.89
50 12.89
40 12.88
30 12.88
20 12.88
10 12.87
0 12.87

 

[Photoman]

Turning the key on = light on. Next with key off unplug the regulator wiring from the back of the alternator. Turn the key on = light off = OK. If the light still stays on then there is a short in the wire going to the alternator. When the key is turned on the light comes on because battery voltage is going through the light circuit to ground through the regulator and alternator. As the alternator spins up and produces voltage the light dims and goes out as there is now no ground through the regulator. If it stays on with the alternator unplugged the circuit is finding ground somewhere else (short).

Let me check something.

OK back. I went over to an old alternator shop about 10 miles from me and asked them about your problem. They said if the above test was good then probably the light circuit in the regulator was bad. The fellow said he had inadvertently shorted out several of the light circuits when trying to test alternators and then had to replace the regulators. One touching of the wrong pins. The regulators would still work but the light circuit portion was bad. HTH

Bill

 

[rhyary]

Hi Bill,
This is a cool test. Very good to know.

 

[yoda-g3]

Are you compensating for temperature?


7.Correct the readings to 80°F:
Add 0.004 to readings for every 10° above 80°F.
Subtract 0.004 for every 10° below 80°F.

Hmmm, I know to do the temp adjustment when using the hydrometer on my solar setup, not doable since these are sealed, but it never occurred to me to adjust for temp when measuring voltage as well. Even with the compensation at 20-30 degrees in my garage that still only gets me to 12.7 ish. A little better then I was thinking but I'll still keep an eye on them. (nice thing is I have a VERY nice charger for my solar stuff that I can use to top these off. I always bust it out after using the winch.)

Turning the key on = light on. Next with key off unplug the regulator wiring from the back of the alternator. Turn the key on = light off = OK. If the light still stays on then there is a short in the wire going to the alternator. When the key is turned on the light comes on because battery voltage is going through the light circuit to ground through the regulator and alternator. As the alternator spins up and produces voltage the light dims and goes out as there is now no ground through the regulator. If it stays on with the alternator unplugged the circuit is finding ground somewhere else (short).

Let me check something.

OK back. I went over to an old alternator shop about 10 miles from me and asked them about your problem. They said if the above test was good then probably the light circuit in the regulator was bad. The fellow said he had inadvertently shorted out several of the light circuits when trying to test alternators and then had to replace the regulators. One touching of the wrong pins. The regulators would still work but the light circuit portion was bad. HTH

Bill

Wow, talk about going the extra mile. I'll go try that out on my lunch break and see what I come up with. Thanks!

 

[yoda-g3]

Photoman - Did the test and it checked out ok. Light stayed off when the harness was unplugged, and it came on when I plugged it back in.

Your conversation with the shop reminded me that one of the places I took to have it tested was having a hell of a time finding the right adapter to test it. I wonder if they fried it.

So in your opinion with the results I'm showing on the AC and DC tests do you think its good? Seems like a lot of people are reporting 14.4v+ for a standard charging voltage and this settles in the 13.6v+ range.

Last what are my options to take care of the annoying light? Is the bad circuit a serviceable item or am I just going to need to get another alt?

 

[Photoman]

Photoman - Did the test and it checked out ok. Light stayed off when the harness was unplugged, and it came on when I plugged it back in.

Your conversation with the shop reminded me that one of the places I took to have it tested was having a hell of a time finding the right adapter to test it. I wonder if they fried it.

So in your opinion with the results I'm showing on the AC and DC tests do you think its good? Seems like a lot of people are reporting 14.4v+ for a standard charging voltage and this settles in the 13.6v+ range.

Last what are my options to take care of the annoying light? Is the bad circuit a serviceable item or am I just going to need to get another alt?

The fellow at the shop said they had particular problems testing the square plug type like these alternators have. He gets in rebuilt alternators (for all vehicles) from some company and tests them before installing them. Through the course of testing them I guess he screws some of them up. He kind of slyly laughed and said he then sends them back to the manufacturer as if they are defective. Not really too funny. So it is possible the company you used for testing did fry it.

In my opinion it sounds like part of the voltage regulator is bad. They are sold as separate items if you would care to just replace it and would probably be cheaper than another alternator. If you do replace it or get another alternator, I would get it tested and ask them to check the light circuit. The shop I inquired at seemed that should be part of testing; although I got the impression that they rarely did it. Mostly just do a full field test and if the alternator is putting out full amps call it good.

We always take a chance getting salvage alternators but so far it seems the majority are getting decent ones.

I don't know what to say about the charging voltage. There are so many things that can affect it and it is within the standard range. I know when I had a deep cycle optima that thing would not top out like a standard start battery and I don't think it was supposed to.

Bill

 

[Hants]

I'll add another cause: excessive load on the AltGood signal circuit.

I have a high-amperage relay for paralleling my batteries. Stock alternator powered it fine (tapped the alt-good signal in the fuse box). 150A replacement would cause the charge light to stay on (relay would close fine). Removing the relay from the circuit caused the light to behave normally.

I'm now in the process of converting to a voltage-sensing control circuit for the relay. Won't be quite as nice when winching, but at least my charge light will behave correctly.