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YACT: Battery or alternator problem?

K

kt

Diamond Member
Here are the symptoms:

Starting up the car is difficult (have to crank it for a long time). IF I get it started and turn on the headlight, the light is really dim. Like when you turn on a flash light and there isn't enough juice. Does this sound like a battery problem or alternator problem? Or none of the above?
 
Seems like alternator. Did you have to jump start the car at any time? How long did you let the engine run before turning the lights on? More than likely, it's the alternator, just my thought.
 
It sounds like a alternator problem and I would start diagnosis that myself, but a bad battery can have the same effect for a short period of time. Does the headlight brighten up if you take the engine off idle or the it run for a little while?
 
Could be battery, starter, or alternator. Go to a battery store or Wal-mart, or wherever and they will check all of these for you.
 
I am guessing the alternator myself. Doesn't the alternator provide the electricity once the engine is running? It doesn't matter how long I have the car running before turning the headlights on and it would still be dim.

Also, I didn't have to jump start the car when I get it started. I am thinking the battery still got enough power to start the car but it is slowly draining away since the alternator is not recharging it.

I was hoping it wouldn't the alternator because isn't that kinda costly to replace? Any idea how much I am looking at to get the alternator replaced?
 
Alternator.

Privce varies widely by car. And some are easy to replace, others aren't. My Accord had a bad alt once that was eventually replaced twice. And to make matters worse, there were 2 alts for the model year and the garage accidentally installled the wrong one the first time, thats why it crapped out.
 
How long have you been driving like this? At this rate that battery won't have enough power to run your car for much longer.
 
It's a car I gave me brother so he can drive to school. This happened yesterday and it has been sitting in the drive way since.

'87 Acura Legend coupe.

-edit-

*ouch* $150 for alternator alone.
 
I actually think it's the battery. My experiences with an alternator is that if it goes out, your car won't work. I've had it happen to me a bunch of times.
 
How long has it been like this? When the alternator is bad, the battery will eventually be drained dry, and the car will no longer start, etc. OTOH, a bad battery can crank slowly and have dim lights, but as the alternator will keep re-charging it (although a bad battery will not re-charge well), those symptoms could last for an extended period of time.
The important thing is to take it in, get it diagnosed and fixed quickly, because a car's battery, starter, and alternator are all inter-dependent, so a failure in one can cause all 3 to fail.
 
You guys may be right now that I think about it. It has been over 4 years since the battery was replaced. It was too dark last night for me to check the battery fluid. Gonna check it tonight under better lighting. I certainly hope it's just the battery and not the alternator. One thing I forgot to mention is the battery light comes on, I would check the car manual for what it means but I don't have it. Thanks guys.
 
Originally posted by: minendo
What does your battery guage read once the car is running?
Click to expand...

not all cars have voltmeters... mine doesn't. 🙁
sounds like alternator, because if it was the battery the car would start slowly and then run better once the alternator was charging.
however, i have seen this same problem with batteries, except it's a little harder to tell by symptoms like lights dimming.. it's more just cranking getting slower and slower over a few days/weeks. but if the lights are dim once the car is running it sounds like the alternator isn't charging, and the battery is subsequently dying because of it.

that's my .02... not sure how useful it is .... 😛
 
I had the same problem. It was the battery that was gone, since it was leaking acid and the battery was about 4 years old. If it was the alternator, the battery light on the dash would have come on saying there is a problem with the charging system.
 
jeez...if u really wanna know without going to a mechanic..get someone else's battery and plug it in.
if it still wanes after a day, its the alternator.

my take=80% its alternator.
 
Originally posted by: xchangx
I actually think it's the battery. My experiences with an alternator is that if it goes out, your car won't work. I've had it happen to me a bunch of times.
Click to expand...

No your car WILL run without an alt. in place. Just not very long as it will drain your battery for everything electrical.
If hes having trouble turning it over it could be the starter... depends on what the "difficulty" in getting it started is (does it just chug and chug then catch or does it kind of wind slowly?)

Sounds to me like an alt. issue as its just not creating enough juice (or none at all) Start the car and put a volt meter on the lines. What's it read?
 
1) Start vehicle

2) Disconnect negative battery terminal

If vehicle dies, it's the alternator. If vehicle keeps running, it's the battery.
 
Originally posted by: rayray2
1) Start vehicle

2) Disconnect negative battery terminal

If vehicle dies, it's the alternator. If vehicle keeps running, it's the battery.
Click to expand...

Yip, the easiest way to test.

 
Originally posted by: rayray2
1) Start vehicle

2) Disconnect negative battery terminal

If vehicle dies, it's the alternator. If vehicle keeps running, it's the battery.
Click to expand...

Thank you. Will try that once I get home.
 
Originally posted by: kt
Originally posted by: rayray2
1) Start vehicle

2) Disconnect negative battery terminal

If vehicle dies, it's the alternator. If vehicle keeps running, it's the battery.
Click to expand...

Thank you. Will try that once I get home.
Click to expand...


I've always heard this recommended against on modern computer controlled cars, disconnecting the battery ground isn't very good for the electronics.
see #8 here

With that said, I vote battery because you're having trouble starting it, with a bad alternator, you're battery would eventually be drained to the point of not being able to turn over at all.
 
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