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New Alternator Voltage Certificate 13.2 too low ?

naxjxj

NAXJA Forum User
Location
Oregon
Just received New Alternator.
Voltage Printout Certificate states 13.2 Volts.

I've read that you always want to see 14.0 .....is this too low ?

It's made in China, but has very good reviews. "TYC" brand.
Appears identical to orig. Denso 90amp


'95 Xj 4.0L
 
13.2 at idle is just fine -- I'm pretty sure the XJ PCM regulates the voltage down below 14.0 anyway

There was just big thread about voltage regulation on here a few weeks ago -- lots of info --search is your friend
 
Thanks.
It doesn't specify what RPM the VOLTS were taken at.

The Amps test certificate (if anyone's curious) are :

42 @ 1,600
63 @ 2,000
76 @ 2,400

and several more, ending up at
117 @ 6,000 (which is moot, as I understand 5,000 is max

Means one has to be satisfied with around 76 Amps.

---
I searched the forums for a long time - over several days - before posting this.
 
Just read entire thread : Nope, nothing at all there about what Volts Output should read.

(other than 1 reference to what many have said on other posts : that 13.x volts is too low to sustain the charging system)

Which goes back to my question & concern about new 13.2 volts output perhaps being too low ?
(esp. for a factory test certificate)

Took nearly 8 hrs across 2 days just to get it out.
(and I have the giant Factory Manual. Part where it says "remove alternator" LOL - that's the part that took so many hours)
 
Last edited:
Put the replacement alternator on.
Put some load on the electrical system by turning on all the electrical equipment on the XJ.
Bring the engine RPM up to about 1,500 RPM.
Check voltage at battery terminals.
Post up your results.


The test results you got with the unit were done with a simulated load at various alternator speed. In real life, alternator speed is usually somewhere around three (3) times the engine speed. In addition, the numbers shown are in Amperage not voltage. Usually, the amperage will be higher and the voltage lower under heavy load. With a good voltage regulator and light load the voltage should be about 14 volts +/_ .

My XJ with a battery temperature sensor only get to 14 volts when the ambient temperature fall below 50 degrees which do not occur often in FL.
 
I've used a new TYC alternator so far it has worked out fine. I don't remember what the test print out said but at idle it had plenty of voltage. I think you'd be ok using that alternator.

If you're concerned maybe try to swap it at the store for another, if it's Amazon either return it or email them telling them in vague terms the alternator is not producing enough voltage and you'd like a replacement. Don't get too specific it often confuses the point with Amazon. If it's something they stock themselves they usually next day ship the replacement.

If it is rockauto, well that's a different kettle of fish. Your going to be stuck with the freight both ways so you might as well install it and then go through the hassle once you know for sure it's bad.

I and others have had a good experience with the brand, I think you'll be ok but follow your instinct.


Sent from my iPhone using Tapatalk
 
Thanks for your review on the TYC : similar to purchaser reviews
I'm going to go ahead & install today.


"The test results you got with the unit were done with a simulated load at various alternator speed. In real life, alternator speed is usually somewhere around three (3) times the engine speed."

Good point that Alt.RPM is distinct from engine RPM ("pulley ratio" says 2.23). Test labels it "Alternator RPM".

This means that test result @ 5,000 RPM of 111 Amps, actually is meaningful, since that converts to 2,200 RPM, a typical speed. Sounds pretty good.
(it didn't state what RPM the 13.2 V where taken at)


"battery temperature sensor"

Sensor's been removed - just some wires tucked under Battery. (prev. operator took it out - said it'd been a problem). It's mild to hot climate, rarely drops below 40, so assuming this won't cause issues ?
(Alternator's never been changed from what I can tell)
 
My Toyota van reads 14.2v at start up then drops to 13 something during driving. Pretty sure my jeeps charge at 14 or close with no headlights or ac running.


Sent from my iPhone using Tapatalk
 
The voltage output on my Cadillac fluctuates based on draw, high 13s at start (replenish battery) then low 13s at idle. Everything I've read about the GM alternators is that running constant 14 indicates a broken regulator and will eventually burn up the alternator.

I'm not sure how the Denso alternator and regulator is supposed to work but I would be surprised if it was not the same
 
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