Alternator Dying! Please Help ASAP!

[blade34609]

Hi,

I have a problem with my alternator not charging my battery.
Somone told me it was discharged battery so I bought a new one with brand new terminals.
But it still didnt soldve it and died soon after cause the alternator wasnt charging it.
So I took my old alternator to Autozone and replaced it with a brand new one.
It worked for about 2 days then while driving home from work tonight:
1st: my headlights got dim
2nd: my stereo head unit light got dimmer
3rd: my tach flopped up and down then finally stopped
4th: my dash lights went real dim
5th: it started to idle real rough
and if I woulda left it any longer it woulda killed the engine.
So, what could it be?
I thought maybe my amp was draning my power like maybe it comes on when I shut the car off.
But i checked and it only comes on when the car is turned on.
Brand new alternator and battery, too.
Any help please!
Thanks

[Kunundrum]

yeah your not getting enough juice, your motor is running off your battery, and that was getting dead.

An Alternator DOES NOT CHARGE THE BATTERY !!! it provides power to electrical components while the car is running. the battery starts the car or runs components while the car is off.

you need a new alternator.

[civickiller]

the alternator DOES CHARGE THE BATTERY thats why if u use a dead battery and use your alt to try and charge it, it kills the life of yoru alt because its too heavy on the alt.

i mean if your alternator is hooked up correctlyas long as the connection is to the battery its all good. i mean the power from the alt goes straight to the battery so if your not getting power to your battery, the wire from the alt to the battery must be cut somewhere. u should make sure you alt is putting out the volts, just because its new, doesnt mean it cant be bad

[Tercel GTS]

autozone alternators are junk anyways, the premium alternators Advance sells look pretty good, I build alternators for a living, and very few parts stores get my approval

[Setanta]

Alternators do charge the battery.

Prolly just a case of brushes and bearings need replacing - cant hurt to have the regulator checked either. Rebuild it or replace it.

[91EF3ZC]

Use a volt meter and check your voltage, but is sounds like you bought a bum alt.
your battery should be resting at 12.6 +/- 1 volt with the car off.

With the car running you should see 13.9-14.4 volts. you will have to bring up the RPM at some point to kick the ALT. on as well. Honda ALT. shut off when it is not needed. it will kick back on when it sees a draw or voltage drop.
Start the car, check your voltage at the battery, then start turning things on, lights, radio, brites, brake lights, ect..... your Alt. should stay between 13.6 - 14.6. then you know if it charging or not.

But like the other dude said, just cause it's new dosen't mean it's not bad. I have seen it before as well. Good luck.

Mike

[rusted]

Originally Posted by Kunundrum

An Alternator DOES NOT CHARGE THE BATTERY !!!

Actually, the alternator DOES charge the battery. The worst possible thing that some [insert favorite losers term] do is disconnect the battery cable while the engine is running. In the EE business, we call this a "load dump" and the 14vdc can spike to 65V for as long as 250 ms; more than long enough to roach electronics. (If anyone wants, I'll be happy to explain at length.)


Step one is to measure the voltage at idle. It should be ~13.5v. Then rev to car up to say 2500; it should rise slightly, say 14. Further, you should hear the engine load down at idle when you turn on the high beams+fan etc.

It's possible your new alternator is FUBAR. It's also possible it's a wiring issue. It's hard to diagnose from what you've said so far.

[blade34609]

I bought one of those portable volt meters that plug into ur cigarette lighter.
The car is at 12.0 volts with car off.
When car is idling it is at 11.6 with radio and lights all turned off.
It drops a little when they are on.
When i rev it up to about 2500 it barely goes up.
It just stays at 11.6 or maybe to 11.7.
It must not be charging right?
Where else can I check?
im reluctant to get another alternator because its the second one ive replaced. Just got this one on thursday.
Got the harness and screw connector on there real tight and secure.
New battery also.
Thanks

[91civichatch2571]

Take it back to where you bought it with your receipt and see if they can do anything.

[blade34609]

Ok I guess I'll take it ova to Autozone tommorow or Tuesday.
I guess it would have to be a bad alternator right?
because its my 2nd one of the same brand alternator.
I think it is a New World or some unknown cheaper brand.
I drove it tonight with just the headlights on.
It stayed at a constant 10.8-11.0
But it started right up everytime (started it 4 times)
BTW, i bought one of those digital volt meters that stays in ur cigarette lighter while u drive.
What brand do you suggest alternator do I buy?
AC Delco?

How much should i spend to get a good alternator.
THanks

[civickiller]

u should measure the volts coming out of the alt, because the alt might be putting out the volts and not just getting to your battery, if yoru alt is putting out the volts then u know theres a break between the alt and the battery. but if the alt isnt putting out the volts then u know u got a bad alt

[azninteg]

Since you have an amp in your car, you might want to invest in a power capacitor soon. Depending on how much your amp pushes out (1/2 Farad capacitor - up to 500 watts, 1 Farad capacitor - up to 1000 watts). Since you don't have a capacitor in your car now, your amp is taking power straight from your battery and your alternator has to reacharge your battery must faster, thus working it harder. Think of the capacitor as a little battery. Your amp would be taking power from the capacitor first and then the capacitor would eventually charge up. A capacitor would stablize your electrical system and reduce a lot of the dimming in you car. good luck man...

[blade34609]

Yea I was thinking about gettin me one of those capacitors.
But, Its only a 222 watt Sony Xplod amp powering a single Jensen 10" Sub.
Any of you got an idea of what alternator brand to buy?
So far the good news is;
I think the alternator is charging but it is not pwoerful enough.
The voltage coming from the battery stays at a constant 11.8-12.1
It doesnt seem to drop below or raise above that. And I have been watching the voltmeter a lot.
I definetly think I just need a better brand alternator that puts alittle bit more power to the charging system.
THanks

[rusted]

It's clear your alternator is not charging and your battery will soon fail; leaving you SOL.

Originally Posted by blade34609

I guess it would have to be a bad alternator right?

Not "have to" -- it may be wiring issues. It's hard to diagnose remotely. But yes, pull the alternator and have it tested.

I do not know if your car has an alternator fuse, another possibility. Anyone more familar with Hondas know?

If you have a friend with a DVM, not the cigarette lighter gadget but the kind a technician or EE uses, then you can make more tests but I hesitate to overwhelm you with details.

[rusted]

Originally Posted by azninteg

Since you don't have a capacitor in your car now, your amp is taking power straight from your battery and your alternator has to reacharge your battery must faster, thus working it harder..

Not really. A large cap stores energy, but only for fractions of a second. Its benefit here is that a THUMP THUMP THUMP flavor amplifier draws very large current spikes for fractions of a second on each thump, but far less inbetween. When drawing that much current, there's voltage drop; more than desirable.

But the alternator actually works equally as hard -- it's like saying "Oh, I'm broke -- I'll just charge this new stereo.." Well, guess what, you still gotta pay for it, it just takes the CC company a few weeks to catch up to you...