270A Alternator installed, but still not 14.4V (1 Viewer)

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May 31, 2010
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I just finished fanagnling a 270A alternator from DC power into my 1994 1FZ.

When I start up I get 14.4 or 14.3V, but after a few minutes it drops down to 13.6-13.7.

Is there an external voltage regulator somewhere?

Or maybe a stock ground somewhere that's heating up and slowing everything down?

I've got 1/0 gauge wire from the alt-battery, battery to engine, and battery to the subframe.

Also, I have 2 optima yellow top batteries. They are both good; I get 12.8-13.1V when the engine is off. I just have a simple parallel connection for them, no isolators. I also have a 10 Farad capacitor.

All these voltages are with the stereo off.

What can I do to get the voltage to stay at 14.4? Just more grounds?
 
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270 amp? Did you have to get a new mounting bracket? I don't think I've ever heard of one that big in an 80 series. What does the shop say about your voltage output?

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It was supposed to be a direct bolt in, but some grinding was required to make it fit. I used the stock bracket, but had to grind it a bit to make it fit properly.
I haven't heard back from them yet.
I had a similar problem with the stock alternator, so I'm thinking it has to do with something other than the alternator itself.


270 amp? Did you have to get a new mounting bracket? I don't think I've ever heard of one that big in an 80 series. What does the shop say about your voltage output?

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e9999

Gotta get outta here...
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I don't know that alternator, but on a couple of my vehicles, the voltage will decrease as the battery is charged more. It is also a function of rpm. On the 80, it may be 14.4 if the battery is low but will then slowly drop to something like 13.9 after a while. On my Honda, it is similar but will even go down to 12.6 (as in alternator going offline?) if I'm idling with a battery fully charged. Makes sense to me, why try to charge a battery that's already fully charged?
Why are you concerned? Anything above 12.6V or so will charge the battery in principle I assume, so if you're in the high 13s it should be OK. The exact voltage is probably just a matter of regulation for the alternator in question.
 
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Why are you concerned?
My audio equipment performs best at 14.4v

What type of alt is it? Install pics?
It's a DC power XP series alt.

I don't have any install pics. I was expecting a bolt in operation. Which should have been a piece of cake since my rig has a body lift and I can access the alternator through the wheel well without removing anything. However, it ended up being trial and error. Now that I know where to grind I bet could do it again in an hour or so.
 
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$600? :eek:

What is interesting is that it is for 98+. According to their site, it's not for an 80.

Makes me wonder if OEM 100 or 200 series alts would work. :hmm:

Any chance you can provide more info on what you ground off? Pic maybe?
 
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$600? :eek:

What is interesting is that it is for 98+. According to their site, it's not for an 80.

Makes me wonder if OEM 100 or 200 series alts would work. :hmm:

Any chance you can provide more info on what you ground off? Pic maybe?
Yeah, that's how much I paid. The weak dollar helps, though.

I contacted the ahead of time to make sure I got the right alternator. I was very clear that it was for the 80 series with a 1FZ-FE engine. The 100 uses a serpentine belt, I believe. I don't have the tools to swap the pulleys.

I have read about people using Tundra alternators with a modified bracket. Photoman, on this forum sells them. Tundra parts are pretty hard to come by here, which is why I ended up getting the DC power alternator.

On the alternator, I needed to grind down behind the top hole on the back, so it could swing properly when the big bolt is in.

Then on the front at the bottom, I had to grind above the hole so it could move along the bracket.

Then I had to grind the top of the banana shaped hole, so the holes would stay lined up through the full swing.

I ground a few places I thought I needed to, but it turned out I didn't. I'll just chalk it up as weight reduction.
 
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Be thankful ur seeing what u are reading. 13.6-13-8 idle charge voltage is perfect. If the alternator is working correctly, u will see, upon starting the FZJ80, a voltage spike to ~15.5 volts - which will rapidly drop to 14.2 volts and then more slowly to 13.8. If u see a voltage of , say , 14.5 volts and it never gets to 13.8 volts, u may find parts of a battery all over the place - dangerous!

And now the real question; what kind of alternator? Pics?

...
 

jvazquez53

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$600.00? $$$$$:eek:. Most alternators are adaptable. A 100 series probably will. I have been looking into a GM one wire, lots of amps and simple. However since my 120 amp is working, and some of my friends have a lot of electronic equipment installed in their Cruisers with the factory alternator, I have not seen the need for spending lots of cash on a high output alternator.
GM one wire alt Wiring hook up.jpg
GM one wire alt.jpg
 
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My audio equipment performs best at 14.4v.

This sounds unlikely as most audio equipment is designed to run at a nominal 12V.

Maybe the problem is the power wire to the amp is too small, so you are experiencing a voltage drop at high power output. A 1000 wat amp is going to consume more than 80 amps, so if you are feeding it with a 14 ga wire, the voltage at the amp may be half of what you expect at full power. A 4 ga wire would be better.
 
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Hey FL

I have the same alternator from DC Power, my truck is an HDJ81. Internal voltage regulator. Purchased in Feb this year, it has performed flawlessly with 1/0 cable throughout. I think you should phone Stan and talk to him.....BTw, I had to modify my upper alternator bracket slightly as well.
I would be checking the system with an electronic tester such as the midtronics (Car Battery Testers and Electrical System Testers - Midtronics) to know what is happening with your system. A professional automotive shop near you might have the right kind of diagnostic equipment. FWIW.

G'luck,
Gord
 
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Be thankful ur seeing what u are reading. 13.6-13-8 idle charge voltage is perfect. If the alternator is working correctly, u will see, upon starting the FZJ80, a voltage spike to ~15.5 volts - which will rapidly drop to 14.2 volts and then more slowly to 13.8. If u see a voltage of , say , 14.5 volts and it never gets to 13.8 volts, u may find parts of a battery all over the place - dangerous!

And now the real question; what kind of alternator? Pics?

...

It's a DC power XP series 270A alternator. I didn't take any pics during the install. I'll try to take some pics later.

I guess it's sounding more and more like this is normal.

$600.00? $$$$$:eek:. Most alternators are adaptable. A 100 series probably will. I have been looking into a GM one wire, lots of amps and simple. However since my 120 amp is working, and some of my friends have a lot of electronic equipment installed in their Cruisers with the factory alternator, I have not seen the need for spending lots of cash on a high output alternator.

My stereo is over 3000W, so I need a lot of power. Most alternators don't make a lot of power until higher rpms, but the DC power alternator make 200 right off idle.

This sounds unlikely as most audio equipment is designed to run at a nominal 12V.

Maybe the problem is the power wire to the amp is too small, so you are experiencing a voltage drop at high power output. A 1000 wat amp is going to consume more than 80 amps, so if you are feeding it with a 14 ga wire, the voltage at the amp may be half of what you expect at full power. A 4 ga wire would be better.

Power supplies regulated at 12v are rare in high output amps. Almost every amp I've looked at has it's RMS wattage rated at 14.4v, and some go up to 16v.

The power wire is also 1/0 gauge.

Anyway, I'm not talking about voltage drop while the music is playing, this is while everything is off. For what it's worth though, the voltage doesn't go past 13.8 once the car is warmed up, whether the stereo is playing or not.

are you getting these readings off the alternator or the amp?

Most of the time I am looking at the reading on the capacitor. However I have double checked the front battery, as well as the back of the alternator. They are the same.

Hey FL

I have the same alternator from DC Power, my truck is an HDJ81. Internal voltage regulator. Purchased in Feb this year, it has performed flawlessly with 1/0 cable throughout. I think you should phone Stan and talk to him.....BTw, I had to modify my upper alternator bracket slightly as well.
I would be checking the system with an electronic tester such as the midtronics (Car Battery Testers and Electrical System Testers - Midtronics) to know what is happening with your system. A professional automotive shop near you might have the right kind of diagnostic equipment. FWIW.

G'luck,
Gord

Thanks, I didn't know anyone else had a DC power alternator. Are you saying yours stays at 14.4v all the time? Where did you run your big 3 grounds?
 
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Model


side by side with stock alt


easy access through the wheel well

weight reduction. this grinding was a mistake as far as I can tell


the hole had to be enlarged. I ground the top of the hole. Also I got a longer bolt. I had to use a nut on the back since the stock alt has a threaded hole and the DC power alt doesn't.


I had to grind off a lot of material along the bottom of the alternator so the stock bracket would fit and slide properly.


One thing I forgot to mention was that I had to cut away some of the plastic for the plug to fit


This is where I had to grind down on the back of the alternator for the holes to line up properly.


ground to engine block


ground to subframe
 
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Medford, OR
Thanks for the pics.

Have you tried disconnecting wiring? Since you have such extensive wiring for your sound system, maybe there is something wrong there that's causing a drain.
 
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Marshall, MI
Go to Steve meade site. He will better answer you questions. I don't know if that alternator has an adjustable regulator. If it is adjustable then you can simply turn up the regulator but you will have to make sure the rest of your electronics will like operating at such a high voltage. Most hardcore stereo heads have separate alternators for the stereo so that they will not harm the vehicle electronics from higher than 14.4v loads. But like i said, go to his site. You will learn so much from his builds and forums.


Steve Meade Designs (SMD)
 

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