CCA s 582

the battery is rated at 12vdc 52AH (amp hour)

 

You know what? I wonder if your alternator isn't putting out TOO much voltage, killing your batteries. 16vdc while revving seems a little high. The factory spec is from regulated anywhere from 14.1 to 14.7.

 

the battery im running is CCA @0 degrees: 570
and CA@32 degrees: 710

 

I run a redtop R34 strictly for cranking purposes with a whopping 830CCA..



http://hypertextbook.com/facts/2001/MelissaNg.shtml

http://www.patentstorm.us/patents/6097193-claims.html

 

the 14.1-14.7, where did you get those figures?

 

^ from the service manual

 

what section, looking

 

Starting and Charging system, under Service Data and Specs

 

i think it is safe to say the alternator will read high when there is no electrical load drawing...???

 

That's possible, but I'm reading it as that the alternator is supposed to regulate voltage to no higher than 14.9vdc.

 

I'll go meter mine, brb

 

Your alternators regulator is screwed it should never be that high.It is overcharging the battery which causes the battery to sulfate the plates.Since i work in a auto shop i have seen plenty of blown up battery,s that are caused by the alternator overcharging.A battery should read about 12.25 volts disconnected from the car,when the car is running it should read anywhere from 13.9-14.7 volts nothing more.Your battery is toast because the alternator is overcharging it.

 

I have had some wierd things happen lately but not consistent enough to figure it out.

A couple of times just sitting at idle without the stereo on the voltage will make a quick drop, but also heard the fuel pump really loud that time so not sure if it was the alternator or fuel pump having issues.

Then one other time sitting at a light a song hit with a lot of base and the car just shut off. I am thinking of getting a better one as this one is the stock one with 5 years and 52k miles on it

 

Mine reads 14.41 at idle, (no ac or stereo) and no higher than 14.45 while revving. With the car off, battery read about 12.7 which is weird, you'd think it would hold whatever voltage the alternator is giving it. But it's literally brand new, so I know it's good.

 

so a new alternator is in my future? any way to swap the regulator? or is this the main heart of the alternator?

 

did you disconnect the wire form the laternator and meter it? if not, could you please...turn the meter so you can see it while revving, rev it to 5500rpm a few times, quickly, and see how high it reads...

again, with the alternator wire disconnected from the battery, straight to the voltmeter and a ground

Thanks

 

I didn't isolate the alternator wire, I just metered the battery terminals. When you meter the battey while running, you're basically metering the alternator's output, that's why you can see it fluctuating slightly with revs. I had my meter facing me while revving. I also revved to 5500 or higher, and a few points in between, holding it for a few seconds.

 

From looking at the exploded diagram of the alt in the service man, there is a separate voltage reg and a diode assembly, but you'd have to take the whole thing apart, and Nissan probably doesn't sell the individual pieces anyway.

 

could you meter it seperate for me? just gotta take off one 12mm bolt

I am really willing to bet that the alternator will show higher voltage when metered seperate from the battery, but would like to see if your figures are consistant with what I got, before I go swapping an alternator.

Thanks

 

a fully charged battery disconnected should read 12.85 volts,installed engine running is normally 13.5 to14.5 any more is over charging.if your stereo is sapping the charging system it causes the alternator to charge constantly instead of cycling on and off which fries the rectifier,sounds like this is whats going on.you need a higher amp alternator.(could also be bad engine ground,would cause same symptoms.)