Alternator Amperage Question

[Klownicle]

99 Honda Passport EX 2WD

I know I have a 90 (88amp) alternator. I've had it tested and my alt puts at max 44amps. They said the alternator isn't reporting anything bad (diode good, etc)

If im needing the more amps. Would replacing the alternator with a stock alt give me my 88ish amps?

Im thinking its the orignal alterantor, so thats 8 years old.

Btw, this is with the alternator in the car. Just wondering what kind of results should I see while its in the car.

[Cat Fuzz]

I'm curious to know how you tested the current output. Just because an alternator is rated to put out 88 amps doesn't mean it's going to produce that kind of current at all times.

[Klownicle]

I have had many different load testing machines get attached. And I've never seen any higher than that.

[Ramblin Fever]

Not sure honestly; mine is a 60amp alternator and when I test it under-load - truck running, A/C, radio, etc on it comes up to 14 volts. I know if it's under that, it's bad.

[Klownicle]

My voltage is fine. I got high 14.6+ with car in normal operation.

The amperage for a load seems just low. I was wondering if that was normal.

Everyone always gives me reasoning saying it will only charge 88amps when the battery is dead or dying.

Ehh. Just lookin for a stright yes and no one seems to give me it lol.

[trooperbc]

Originally Posted by Klownicle

My voltage is fine. I got high 14.6+ with car in normal operation.

The amperage for a load seems just low. I was wondering if that was normal.

Everyone always gives me reasoning saying it will only charge 88amps when the battery is dead or dying.

Ehh. Just lookin for a stright yes and no one seems to give me it lol.

44 amps under load for a 90 amp alternator is not within any spec.

not under load, and good battery, consider ~10-15 amps.
under load, and good battery, consider ~10%-15% from rated amps to be within spec. amps will vary with temp and load.

but you are ~50% of rated spec.

i supsect the alternator, but do the normal checks of the
*battery*
*wires*
and especially **grounds**, don't just eyeball them, remove and shine up and reinstall.

but consider, the test does need to be *under load* and at 1500-2500 rpm.

are you experiencing *any* symptoms of a charging system not putting out enough ?

//bc

[Klownicle]

My grounds are fine, My battery is fine.

I get 15.+ after a highway drive, and 14.6+ idle on a fully charged battery.

The only problem im having is my audio system (i've been told by many people 90amps is fine) is causeing my voltage to drop. Its as if my alt isn't handling the load.

Im getting upgraded wire to go to the amps and then adding a audio stinger battery to the back. Hopefully this may help offset. But ehh.

Just seems like the alt isn't handling loads properly as it should.

All the tests were done at high rpms (2000-2500)

[Ramblin Fever]

Your alt may NOT be able to handle the load, you did mention it was 8yrs old??

That is OLD for an alternator, honestly, you've had very good luck. But I would think to go ahead and track a new one down so when this one does go, probably in the very near future, you have a new one to slap in.

Make certain it is a Bosch, Isuzu, or Napa alternator. Do not waste your time with parts retail store alt's - you'll be replacing them every week.

How old's your battery?? If it's fairly close to the same age, they usually take a dive around the same time.

FWIW - my rig only came with a 60amp alternator; my original crapped out at 49k miles, just barely inside warranty period - this was with running auxillary lights 55% of the time, running the stock stereo system around the campfire without truck running 25%, CB radio, cell phone, air pump, jumping our boat battery twice, etc.

2nd alternator - crapped out about 50k later

3rd alternator - some cheap parts store alt, I didn't know better then; it lasted 2 weeks.

Then I wisend up and got a Bosch alternator with a 2yr warranty; it's been in for 4yrs, with running even more auxillary equipment from time to time.

When it goes, I'll buy another Bosch in a heartbeat - not cheap, at $175+, but worth it.

You mentioned your audio system causing your volts to dip, but you don't say to how low - what's it reading on the volt gauge with audio system on, truck running, etc?

BTW, 2-2,500 rpm's is not high on this engine. My engine's barely moving at 2k rpm's.

Don't 100% rule your battery out either, if your battery's not holding up, the alternator's getting drained that way too.

[Klownicle]

Battery is good brand new.

Secondly, im running 1000rms however, i've been told the quality of my amps isn't the grestest, so there not doing that much of wattage.

Thirdly, they dip to 11v.

I can't find the bosch alternator locally. Advance Auto Parts wants to sell me one for 200$ its a worldwide brand (says its a hitachi oem or somthing like that). No one offers any good brands. There is a napa autoparts store locally what brand do they sell?

ALSO! Freakishly, the voltage was 16.6v today on a fresh start in the morning. It went down to 14v after the car was on for about 15minutes or so. And after a long hard run on the highway one night, I got home checked the voltage it was 15.5 and went down as the car idled.

I don't know much about electronics in alternators but it seems mabye the regulator might be shot, and thats why its not handleing the loads properly.. but autozone and advance autoparts said the alt was fine. Sooo this is very confusing. Anytime I get it tested at this joints the car is already warmed up and hot. Last time I had my audio system pumping while the guy was testing the alt, the max amperage was 26amps and 14.4v. Again 90amp alternator. Seems noone can test it right lol.

[trooperbc]

time to change that alternator. you are damaging your battery as well.
be aware -- you won't be looking for a bosch alternator. you want the oem alternator that has been remanufactured by bosch. they really should be available anywhere worldwide. check local independent parts stores. even if not stocked, they can order one in a day or two.

//bc

[Klownicle]

Well, I called napa auto parts. Im getting them to order a bosch alternator. Its 245$ and then the core is 100.29. I hope its worth the extra money. I assume that im paying for a high quality alternator that I won't have any problems with it.

*hopes for the best*

I sware if I put this alt in here, and it still is having problems. I might cry..

[Ramblin Fever]

They've gone up in pricing - wow!

Don't know what they say on them now, mine actually has the Bosch name right on the alternator, bought it 4.5yrs ago though.

Can't say how good it will work for the individual owner, guess it depends on how much wattage you're asking it to provide for your stereo equipment. I have just your basic head unit, with upgraded front speakers and stock speakers in the rear, but I do not have anything special audio wise.

Auxillary lights are a different story, have plenty of those, along with CB radio equipment, air pump, etc and I run trailer lights when need be.

[FL 3.2L]

Mine has worked flawlessly for a couple of years. Nothing but stock in the truck except a basic HU.

[Klownicle]

Got 15.5 this morning went down to 14ish once warmed up. Either way if this is the stock alt, I guess regardless it can't hurt to change a 8 year old alt.