Chino

iTrader: (1)

This is what was wrong with my car's electrical power...

-Car would hesitate to start at times. At times it made a really loud banging noise when it lacked power to get it started. Almost like a hammer being banged against my engine.

-All my lights (headlights, dash, dome, you name it) would dim horribly when I applied the brakes, flash my brights, turn on my turn signal, pump up my bose (stock) radio, or when using my power windows.

-Some speakers would go off for a few seconds from lack of power and then resume to normal. Especially when I hit the brakes.

So I said to myself "Ah, its time to treat my car to a nice and powerful optima red top battery". But first I had to check the alternator to make sure it was not my alternator not charging my battery up. So I took her into Pep Boys and had the battery/alternator check up done to make sure the alternator was recharging the battery properly before purchasing the Optima Red Top. The test came back negative, my alternator was fine. So I purchased the battery. This was two days ago, and my car started up like a nuclear power plant! I had my stereo cranked all the way up, I was pressing down on all the window buttons, flashing my brights, and had my AC on blast all at the same time. Not a single sign of lack of power in my car! I'm telling you it was like I had pluged my car into the wall rather than using a car battery. Yesterday was the same.......but today.....it started all over again! Someone please tell me I'm not going crazy! I would hate to damage my beautiful Optima battery! S.O.S! Help!

BluFlame

iTrader: (2)

Try this: start the car, disconnect +battery terminal, turn on everything, see if the car stalls, then its the alternator.
My lights go dim when brakes applied, with new alternator.

Chino

iTrader: (1)

I'll give it a try. Question is does your stereo go off momentarily too? I asume you mean your headlights. But what about the clock, radio, and gauges? I also forgot to include that my car looses power. Almost like the same type of power that you loose when turn on the AC, except it only last a second.....I'm going to try your suggestion. Be right back...

GrkMchn

if I have my lights on before I start my car, the lights dim when it starts then goes back to normal, when I turn on my AC or hit the breaks, the lights dim..I had my altenator and batter replaced last june...

s0ber

iTrader: (7)

sounds liek your alternator is about to crap out. take it in for a free one if your a 97+ i think...

xHypex

iTrader: (1)

I've used this method before as well, but do realize it is possible to create problems while doing this. The battery absorbs spikes from the alternator, so disconnecting the battery while running the alternator leaves a possibility of frying things (i.e. ECU, etc); proceed at your own risk.
-hype

s0ber

iTrader: (7)

i've done it plenty... never broke anything =\

xHypex

iTrader: (1)

I didn't say it couldn't be done. I just said to be forewarned
-hype

s0ber

iTrader: (7)

i know

aznvegeta

I had the same symptoms. I purchased a new battery and changed my terminal cables and it still didn't fix it. It turned out to be my alternator.

TylerBorg

iTrader: (3)

Pretty sure its called Rectifier Ripple

gmahn

Disconecting a battery terminal while the engine is running sounds like a bad idea... this article may back it up.

http://cartalk.cars.com/Columns/Arch.../April/02.html

Chino

iTrader: (1)

Ok, I turned on my car and while it was running I disconnected my positive battery cable. The car kept running fine. Then I turned the AC to full blast as well as the radio. I started to hold up all the power window buttons and flashing my brights. It was a sensational match up between me and my (alternator I guess). My car would loose so much power my radio would turn off and all lights would dim horribly. I think I almost got it to turn off but there was just enough juice (provided by the alternator I think) to keep my car running.

1) Does this mean I need to get me a new alternator to restore full power?

2) If so are there any other alternators that are better than Nissan's OEM?

3) Does everyone agree that I have a half dead alternator? If so will this damage my new and beautiful Optima Battery?

Thanks for all your help fellas!

P.S. If I only turn on my battery my lights, windows, and radio are seriously under powered. So I'm assuming my alternator is DEFINATLY not charging my battery.

jvienneau

Excellent way to trash the electronics in your car. Never disconnect the battery with the car running (no matter how many times or or others have gotten away with it before). if you want to know if the alternator is working, buy a cheap voltmeter. As for your test, it doesn't prove anything. The alternator needs the battery to regulate and it's output is probably 10% of rated current at idle. From your original post, you probably have a bad connection somewhere.

Chino

iTrader: (1)

Hey BluFlame told me to do it!

Chino

iTrader: (1)

Here are the test results from PepBoys

Battery voltage (volts): 4
Voltage drop accross terminals (volts): 9
Starter amp draw (amps): 12
Voltage supply to back of alternator: 14

They said my alternator was fine, but my battery was bad. Does this match up with the results from the diagnostic test? Thanks.

s0ber

iTrader: (7)

sounds right

MChapel

iTrader: (1)

...and if he told you to jump off a bridge???...

Entropy

iTrader: (1)

At first glance I would say yes, this sounds right.

However, you just got a new battery and it is an Optima even. There is a possibility that it is bad, but let us put that aside for a moment.

They said the voltage to the back of the Alternator is 14V, which is nominal. What is it to the battery though? That voltage has to reach the battery for it to charge. That is why I said to check the battery terminals while the car is running. You should get about 14V still (give or take for draw).

The other possibility is that you are drawing some pretty good voltage from something while the car is off. An interior light being on could do that. I don't think that is it though, cause the car should be fine once you got it started.

At this point, I am leaning towards a short somewhere in your charging system. Honestly, I would take it to a trusted mechanic or a dealership (that doesn't **** you around). Finding the voltage to the battery during operation would shed some light on this though... anything below 13V would make me wonder, and I would rev the engine a couple times and then bounce the car (physically) to see if you can get it to drop (the voltage).

HTH

MaximaMoJo

It also could be a draw from a bad starter. I would just take it to a trusted repair place. You could spend a lot of money replacing things and it could just be a loose or bad connection.

Chino

iTrader: (1)

Anyways my battery seems to be charging okay now. Hear this when I hit my brakes I hear a clicking sound. The dimming of my lights happened when the clicking was heard. Could my brake be tangled with some kind of wire? I still plan to get a voltmeter to check the voltage. I'd like to thank everyone for their help.