my battery light has been on for a few weeks now, but hasn't caused a problem so I didn't worry about it. but, about 2 weeks ago everything in the car started to die on me (radio, lights, etc) so i left it alone for about 24 hours and started it up again and it drove fine. got the alternator checked and its putting out 14.7v @ idle so thats not the problem. last night the same thing happened, everything started to die again. What could the problem be? battery?
btw its a stock 94 ex

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dyases &raquo;</TD></TR><TR><TD CLASS="quote"> What could the problem be? battery?
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um, yes.

 

the only reason the battery light comes on is because of the regulator in the alternator. So the battery is not the problem. It is definietly the alternator.

 

stupid

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EF9_SiR &raquo;</TD></TR><TR><TD CLASS="quote">the only reason the battery light comes on is because of the regulator in the alternator. So the battery is not the problem. It is definietly the alternator. </TD></TR></TABLE>

yeah, that seems most likely, its is unlikely to be your battery unless it is in a really really poor state and can hold virtually no charge but this would happen over time so you would have noticed when you went to start your car..on second thoughts however the battery could have an internal short, this usually happens when the battery gets really old and lead sulphate crystals build up on the plates causing distortion...this is only likely if your battery is old or has been through multiple discharges (and even then its unlikely) lol... don't rule it out...

 

replaced the battery today and it starts up now just fine, but the battery light is still on although it goes away at about 6k rpm then comes back.

 

Change your alternator before your battery starts dying on you.

 

if the alternator is bad why does it put out 14.7v?

 

How did you check the alternator? You should check it under load. Turn on all the electrical stuff in your car and then check the voltage.

 

yeah it does sound like the alternator now... when under load it may not be supplying enough current.. when the battery voltage is higher than the alternator voltage the red light will come on.. the only other thing i can think of would be a short circuit which only occurs when the light comes on...

 

amperage is your enemy here. who cares about how many volts its putting out. Its all about the amps.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EF9_SiR &raquo;</TD></TR><TR><TD CLASS="quote">amperage is your enemy here. who cares about how many volts its putting out. Its all about the amps.</TD></TR></TABLE>

what are you talking about?

V=IR

Current = Voltage/Resistance

At a certain load voltage is directly proportional to current..

If the voltage from the alternator drops below that of the battery then the battery will begin to discharge (and the light will come on) end of story.

I think you mean power output.

 

the light stays on all the time but it never causes a problem untill i'm using the radio, lights, etc.. so that means that the alternator isn't supplying enough current under load right?

 

the word is 'power' under load, but yes that is the way it seems..you need to measure the voltage when under load, if it doesn't read around 14.3 to 14.4 with a fully charged battery then most likely it is the alternator...fix it quick or you'll kill your new battery, car batteries are very sensitive to deep discharge.