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85 Nissan 720 4x4 2.4 12.22 Volts while running.

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Hi Ya'll,Back in 4-23-18,my battery bit the dust.It was less than a year old and my alternator was over charging and it put the battery in a early grave.They gave me another battery under the warranty.The alternator was reading.15.6 volts and the relays under the dash were clicking,but the  auto part store that I have a lifetime warranty said alternator was good,so I went to another part store and they also gave me a very high reading,but said it was good,finally two days later,the alternator read 12 volts and the auto parts store gave me another battery under the warranty.So over charging is not bad to them.But any way,when I got home from work today,my battery light on dash was flickering,and the volt meter  on gauge panel was reading about 12 volts,so I got my meter and it read 12.2 volts,battery read 12.7 volts.Time to go to Auto part store and see what they read.I hope it is the alternator cause it will be free.The volt meter in truck was reading high,so both might be bad.Do you think my Pink Floyd  music caused this..The reading on my alternator is usually 14.5

Edited by Thomas Perkins
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A fully charged good battery is 12.65 or so.


Does your horn work? if yes then the fusible link is ok. This is the link that allows charge from the alternator back to the positive battery terminal


Have it running and disconnect the ground cable. If it stops the alternator is definitely not putting out

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We'll,Mike,I believe this alternator is overcharging the battery also.I went out and started it,the battery light does not come on and volt gauge on the truck reads about 14.5,I got my meter out and it reads 14.45,horn works,took negative battery cable off and it stayed running.Turned engine off and battery is reading 13.38. Going to blow the battery up.Last time it killed the battery.The battery was 12.75 when I got home today when the alternator was putting out 12.22 volts.In order for me to get a new alternator it has to read bad,when it reads overcharging,they say it's good.This happens every time the alternator goes out.I don't keep my tool box on my truck any more.




Edited by Thomas Perkins
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I know idiots right? If it read 50v it would be 'good'.


My 2002 Altima alternator in my 710 reads 14.4 - ish and that fine. You need about 2 extra volts to push a charge into a 12.6 volt battery. I've had 13 volt charging alternators and the battery didn't like that. I never read the battery voltage but it turned the engine over like the battery was  low. 


If the alternator is putting out 12.22 that should qualify as a fail, no?

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  • 2 weeks later...

What he said.


You can't force voltage in to a 12.5-13.0 volts battery (IOW, charge it)   unless you have more voltage than that.  


Around 14.5V is what you need....as mentioned.   If you don't have that, your alternator isn't cutting it.  I think that 15.6 is to much.  Pull the alternator and put it on a machine.  I bet that the "Techs" at your local auto parts place wouldn't be concerned w/to much voltage.


Your battery won't like being over-charged.

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Hi Ya'll.I got off early to day to fix a couple of leaks under my sink in the kitchen,I fixed one then found another one,the facet is leaking from the cold water turn on knob,so I took off and seen that it had water stains on it,been leaking for sometime.Didn't ever notice it cause it is in the back of the cabinet and I never go in there,wife found one leak.But anyway on the way to Home Depot to get a new water Facet,I stopped at Autozone,my volt gauge in the truck started staying at 12 volts.Same exact thing happened 5 years ago.They tested the battery and said it was bad and they couldn't test the alternator with a bad battery.So I stopped at Advance to see what they would say,same thing.So I got my facet at Home Depot and took my battery out and got a new one from Walmart,model number 24,700 cca.975 reserve,it was over a 160 bucks,it went up 50 buck since 2017 when I got the last one,So I installed it and the volt gauge in the truck still was on 12 volts,so I went back to Autozone,and this fine lil honey did the test,said my battery was good and I started it up and she tested the alternator and said it was bad,I told her I had a warranty and she looked it up and it was replaced back in 2017,same time as the old battery.They don't stock old Nissan parts,just like last time,they had to order it and it will be in at 9 am in the morning,so I will take this old alternator out and I have a new gates belt I bought last week from Ebay.I've had my 720 for 28 years and it repeats it self.When I checked it not long ago when my volt gauge in the truck was at 12 volts and my digital meter read 12.2,I knew it was going out,it usually will over charge for awhile,it made my battery go up to 13.2 volts,never goes past 12.76 when everything is good.Last time in 2017 when it started overcharging,it made the relays under the glove box chatter.

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Just got finished putting my new alternator,belt and battery in.Repainted the skid plate too.Mv volt gauge in the truck is back to normal.Here some pictures.The second time that the battery and alternator went out at the same time.












Edited by Thomas Perkins
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