Is my alternator bad, or my battery bad? Or something else?

Question

I have a 1994 Saturn SW2. Here is what it has been doing, and what I have done:

The radio and auto seat belts will intermittently work or not work, or flicker on and off...and the motor will occasionally act like it is going to die, but then pick right back up again as if nothing has happened. The ABS system has been acting up on me as well. The battery light will flicker sometimes. When I try to crank the car it sounds like it is struggling a little bit to get the starter motor to turn.

I took a voltmeter and checked the battery when the car was turned off, and I got a constant measurement of 10V.

I started the car, and tested it again with the voltmeter. This time, it would give me 10V, then jump to 13V, then go back to 10V, then jump to 13V....back and forth every twenty seconds or so.

I turned on the headlights and radio, then checked it again. This time I got a fairly constant reading of 13V, and only occasionally did it fall below that.

Bad battery, alternator, or else?

Oh, and if the only advice you have to give me is "Buy a new car...yours is a 14 years old....what do you expect?" or something like that...please don't bother.

Answer 1

coming from a mechanic for 10+ years this is what you need to do. first unhook your battery and pull it out, if you have access to a charger, hook it up to a battery charger and charge it for 6-8 hrs. on a trickle charge. if you don't have a charger you could get it charged at a number of reputable battery shops. or you could buy a new one if you like, but recharging a good battery is just as well. while thats charging remove and replace your alternator which you could find at napa or reputable parts store, you shouldn't have a problem finding an alternator for your car. once your battery is charged reinstall it and you are done. like new again. by the way there is nothing wrong with a 94 saturn. have fun.
p.s make sure you don't try to charge up your battery with the new alternator, you will definitely burn it out.

Answer 2

Dear Miss Jessica If your battery keeps failing, there are reasons for this # 1 Defective in manufacturing # 2 Hitting potholes breaking inner connections that hold battery cells together to aquire a full 12 volts, each cell puts out 2 volts, X 6 make 12 volts. Testing the battery is mainly with a volt meter, you can do this one by yourself. It should read in a healthy battery 12.6 minimum. When the vehicle is running, the battery should read 13.8-14.0 If the reading is higher then this like 15.0, the charging circuit (the alternator) will eventually fry the battery from (over-charging) causeing a defective state. So, take the battery out, disconnecting the green or black battery cable first, take it to a station, ask to have it fully charged, costs about 10.00 & "load test the battery. Re-install the battery, if the battery is in the same condition, Either reason number 2 is at hand or the alternator burned the cells.

Answer 3

Yours was a VERY GOOD question, and I can give you the answer ... you need a new alternatior. If it was the 'battery' that was 'bad' it would have given you a 'very low' or NO 'voltage' ... but the 10-13 volt 'rise' when you turn the car on, and the 'steadiness' when you turn on the radio and the lights tells me that your alternator is bad. Now all you have to do is 'find one' ... your car is 'not quite an antique' so you may have some 'problems' with it ... but I hope not too many. Sounds like you have a 'really cool car' but nost people won't see that until it's an 'antique' ... and many won't notice until it's 20-25 years old.

Answer 4

First make sure your fan belt is in good shape and tight .. .
I would suspect its to do with the alternator , and as a result your battery is not getting a good charge .. it will switch back and forth to battery power..your car battery should read be at a steady 13 to 14 volts with the car running ..Tighten the belts , clean the and tighten the battery terminals , and check the connections on the alternator and wiring to see if it isn't touching any hot spots and burned the insulation , it may be a bushing going or a bad winding or armature ..on your alternator ..
.. take the alternator off the car and head to your favorite auto parts store they can test it for you and they normally don't charge for it .. test it a couple times and tell them whats going on ..if its bad ..then you know what to do .good thing Saturn parts are relatively cheap to buy ... but after you install the new one .. make sure you charge your battery up with a charger and check the water level ..
good luck

Answer 5

if your alternator was bad, it would drain the battery and the car would die, especially with the radio and stuff on. The first thing id do is go tighten the battery cables and make sure the battery is strapped down tightly. Of course the battery is much cheaper than getting a new alternator, so maybe you should try that first.

Answer 6

Here's the short anwser.
Cruddy battery posts.
The alternator can't get a good reading from the battery.
And your volt meter isn't accurate.

ADDED:
Oh, I just thought of something else. An intermittent short in the starter power wire from the battery is it melted to the exhaust manifold or pinched or frayed rubbing on the frame or engine?
Just a thought.......

Answer 7

My husband is what you call a shade tree mechanic- and this is what he said. He said the battery should be reading at 12 volts- even when off. His thought is that the battery is bad but that it is just a symptom of the problem. He is guessing a possibility of a bad voltage regulator.

Answer 8

Make sure your battery isnt coroded and that your cables are clean to that way it is gettign a good connection. if all is good there I would def say it was your altenator. And some places like auto zone around me will check them for u and tell u if it is bad before u buy a new one.

Answer 9

Check the wiring harness at starter and right of the battery.
Check on left fender where the harness connect to.

Answer 10

Alternator. Or voltage regulator, which is usually part of the alternator.