mjrage

if my alternator was bad, I could jump start the car, drive it around, and then shut off, then have to jump start it again, drive around, etc.. since the initial charge is there?

mjrage

ttt

C-West Civic

Yes. Your alt is there to recharge the battery. Its not need to keep the car running.

Turbogixxer

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by C-West Civic &raquo;</TD></TR><TR><TD CLASS="quote">Its not need to keep the car running.</TD></TR></TABLE>

No, it also keeps the battery charged so that the battery does not die off of the load that the car takes.

Best thing to do is to get your battery/alt checked.

TheKamikazeSquirrel

When your car is running, the electrical system is run off of the alternator, not the battery. The only time the battery is drained while the engine is running is if the demand for power exceeds the limits of the alternators charging capacity (i.e., say your alternator makes 75amps max, but you run a subwoofer amplifier that pulls upwards of 50amps of power draw, like a big 800-1000w amp. Your alternator cannot supply this mch power, so the battery is drained). If the car runs perfectly once it is up and running, but will not start when turned off, then your battery is dead. It has no cranking amps to start the car with, and if the alternator is unable to charge it after the car is jump started, then is has been drained to the point that it cannot recover from it. I'll bet you just need a new battery, but like the other guy said, you should have the entire charging system checked anyway. Make sure they test it with the car off, and with the car running to see how well the alternator is charging under a load.

I learned all of this the hard way when putting my loud *** stereo system on the Civic's tiny electrical capacity, but for more info on the way the alternator works and how it interacts with the battery under power draw, read up on this site:

http://www.bcae1.com/

If that link doesn't take you right to the charging system page, then just scroll down the left hand window and click on #42: Charging system basics. Its got a ton of useful info, but the site is mainly for the car audio enthusiast.

Hope that helps. ---D.

mjrage

I just put a new battery in about 4 days ago.

I can jump the car now, drive about 5 miles with no stereo, a/c, etc.. and died.

I figured the new battery gave me the 50 miles I drove today, but the load from the car just drained it. I turned it off and on at least 5 times thoughout the 50 miles.

Great link by the way.

TheKamikazeSquirrel

Do you have a high powered audio system? Anything more than 30 or so amps of power draw will kill a regular battery in about two weeks. If you have a really slammin' system thats pulling 80-100 amps of draw (and shakin' your neighbors couch), you'll murder that water battery super fast unless you get a bigger alternator and charging cable, or invest in a gel cell battery like an Optima Yellowtop.

Now, if you have no big stereo, just a deck, then you need to look into other options. Either the alternator is on its last legs and is running the car fine but cannot produce enough power to effectively charge the battery, or you getting a parasite draw from somewhere (meaning that a blown fuse or relay is constantly drawing more power than it should, causing the battery to fail and the alternator to be stressed too much). Either way, you'll never know until you get the charging system fully checked. Auto parts stores can do for you, but if have a trusted mechanic, go with them. To check for parasite drains is a PITA, because each fuse and relay has to be individually checked for disproportionate power draw.

However, from you last post, it sounds as if the alternator is on the way out. Does it whine at all? A whining alternator is a sure sign of failure. ---D.

mjrage

Ive got a honda cd player and drove the car all day without it on and without any kind of air flow.

This draw could come from a bad main relay maybe? if you change the fuses under the dash and put in more amps than what it calls for that should be fine correct? Ill have the charging system checked after I use my battery charger tonite.

Thanks for all your help. There was a cheap obd1 b16 alternator for sale so I picked it up for 50$ just in case.

Turbogixxer

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mjrage &raquo;</TD></TR><TR><TD CLASS="quote">I just put a new battery in about 4 days ago.</TD></TR></TABLE>

"new born babies die too" Just because it is new, does not mean it is not at fault.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbogixxer &raquo;</TD></TR><TR><TD CLASS="quote">Best thing to do is to get your battery/alt checked.</TD></TR></TABLE>

Until you test it, you are just guessing at what it is.

TheKamikazeSquirrel

Listen to this guy. I gave you several reasons of what could be happening, but until you get that charging system checked, you won't know for sure. But from what your saying, I say the alternator is toast. How many miles are on the car? More or less than 100k? ---D.

TheKamikazeSquirrel

On seconed thought, forget how many miles the car has. Just get it checked and let us know how it went. I hope you get it worked out...electrical systems are really frustrating, but they ususally are pretty straightforward when it comes to fixing them. Read up on that site real good, it will give you a great understanding of how the electrical system in a car works and reacts to power fluctuations (Remember, knowledge is the only way to stop from being ripped off at auto shops. When I drove Nissans, I learned about engines, when I switched to Honda, I had to learn about electrical systems). ---D.

mjrage

Thanks for everyones help. Ill have it all checked out tomorrow after I get the battery charged up so I can at least drive it.

the jdm motor has hopefully around 30-50k

RCautoworks

Here is how to test the alternator


TESTING
Voltage Test
Make sure the engine is OFF, and turn the headlights on for 15–20 seconds to remove any surface charge from the battery.
Using a DVOM set to volts DC, probe across the battery terminals.
Measure the battery voltage.
Write down the voltage reading and proceed to the next test.
No-Load Test
Connect a tachometer to the engine.
CAUTION
Ensure that the transmission is in Park and the emergency brake is set. Blocking a wheel is optional and an added safety measure.


Turn off all electrical loads (radio, blower motor, wipers, etc.)
Start the engine and increase engine speed to approximately 1500 rpm.
Measure the voltage reading at the battery with the engine holding a steady 1500 rpm. Voltage should have raised at least 0.5 volts, but no more than 2.5 volts.
If the voltage does not go up more than 0.5 volts, the alternator is not charging. If the voltage goes up more than 2.5 volts, the alternator is overcharging.
NOTE: Usually under and overcharging is caused by a defective alternator, or its related parts (regulator), and replacement will fix the problem; however, faulty wiring and other problems can cause the charging system to malfunction. Further testing, which is not covered by this book, will reveal the exact component failure. Many automotive parts stores have alternator bench testers available for use by customers. An alternator bench test is the most definitive way to determine the condition of your alternator.


If the voltage is within specifications, proceed to the next test.
Load Test
With the engine running, turn on the blower motor and the high beams ( or other electrical accessories to place a load on the charging system).
Increase and hold engine speed to 2000 rpm.
Measure the voltage reading at the battery.
The voltage should increase at least 0.5 volts from the voltage test. If the voltage does not meet specifications, the charging system is malfunctioning.
NOTE: Usually under and overcharging is caused by a defective alternator, or its related parts (regulator), and replacement will fix the problem; however, faulty wiring and other problems can cause the charging system to malfunction. Further testing, which is not covered by this book, will reveal the exact component failure. Many automotive parts stores have alternator bench testers available for use by customers. An alternator bench test is the most definitive way to determine the condition of your alternator.

mjrage

i was looking in the fuse box today and noticed there was a 7.5 amp fuse in the 15amp slot for the alternator (it oculd of been a 10 in a 15 or a 7.5/10 I dont remember...) either way, if too low of fuse was in what does that mean? could it cause my alternator not to work?

RCautoworks

The fuse would blow, but change it out anyways.

mjrage

if the alternator fuse was blown, which i think it was, that would cause my alternator to spin but not charge since its running off the belt?

RCautoworks

It would not charge because the fuse was blown.

mjrage

hmm..would it throw a code at all? maybe ill charge the battery and i already replaced the fuse and see what happens.

dRo15

no i don't think it should throw a code at all...as for this other guys problem...as you guys stated already...it does sound like his alternator is done...of course it could be his new battery...but more than likely its not his battery since he bought a new one and replaced it already...

an easy way to check if the alternator is dead is once you start your car, unhook the battery teminals from the battery and if the alternator is still good then your car should keep idle...if your alternator is bad, then your car should die once you unhook the battery terminals from the battery cuz that means your motor's taking its power supply from the battery when the car is started and not the alternator like it should be...

a litter simpler way to look at it is
battery: used to start the car
alternator: supply power and recharge the battery once car is on

of course you always need to take consideration about what other loads you have on power supply needs...i.e. stero system...