charging help

[97bluse]

Good afternoon all

I wanted to see if any one has any ideas on my issue with charging. My 97 maxima 5 speed 150.000 miles SE. One day driving batt light came on. When I got home Tested the volts at Batt. the were low 12v on the dot. I figured it was alt. Got one from junk yard had it tested at auto zone and had the old one tested both seem good. Put the old one back in and it work fine for two weeks. Then symtoms came back. Batt light came on car would still drive. So while in fourth gear shut car off and jumped it at like 35-40 mphs and light would stay off untill car came to a stop. Then Batt light comes on again Checked every thing I can think of. Cont, between batt and alt was good so ruled out that wire. all fuses seem to be fine. I dissconeccted big wire from alt. leaving just the 2 wire that are clipped in to alt, with car running not getting any thing from alt. I am getting volt from white and red wire in the alt clip(batt indicator light) assuming both alt are good, Can I mannuall jump the volt reg frome battery or something. Thinking maybe theres a short from ing wire to alt? when key turned on does that turn on volt reg? If so ...volt reg wont come on if it gets to volt when the key is turned on right? wich would cause alt to not put anything out right? I do most of my own work on my cars but never ran in to charging issues like thi...Uassly either battery or alt...Just replace and good to go....this sux..my only car...need to get to work...

[Nahkapohjola]

Read
http://www.cardomain.com/ride/748507/5
http://www.cardomain.com/ride/748507/10
http://www.cardomain.com/ride/748507/14
http://www.cardomain.com/ride/748507/23

...then check all connectors, wiring, and replace/repair the (?) rotten plus cable connectors AND whole gnd cable.

Add extra gnd wire from alt -to- engine -to- chassis.

Open & clean alt 'casing' and ensure healthy grounding between all alt pieces by spraying contact grease...

[ctwright]

Do everything first person posted, and also check to see if you need to add water to the battery, make sure the alternator belt is good and tight, with the engine running the voltage at the battery should be around 14.4 volts, give or take a few. After cleaning off the battery posts if you rub some petroleum jelly all over the terminals that will help prevent oxidation.

[Nahkapohjola]

One issue more; possibly a cause for fried aternator voltage regulator, and/or intermittent CEL -light without code: loose battery connectors.

The std battery pole connectors are of poor quality - if you loosen and tighten em too often, or overtighten: The connectors metal stretches, and eventually it becomes impossible to get em tight. Loose (or oxidized) battery connections mean that charging has 'no load' and voltage level flucuates, gets spiky. These spikes, overvoltage, tends to kill electronics.

Simple test: If after tightening you can get either battery connector off by hand, replace them with better ones; few bucks apiece.