Battery light come on when idling (1 Viewer)

[TXLX470]

What could be the reason why battery is not charging at idle speed? Battery light goes off when the RPM is above 1.5 to 2K and comes back on when it's under 1K. I have a cigarette lighter volt meter and it goes to 13V+ when driving and then it comes down to 11.5 to 12V during traffic or at a traffic light. I checked the belt and it seems on and belt tensioner is seems to be ok as well. Does this indicate that alternator is reaching it's end of life? My 98 has 169K miles.

 

[tbisaacs]

It’s time to replace it

 

[nissanh]

If you have the OEM alternator, just replace the brush kit. OEM brush kit is about $15 and call it done. Make sure to disconnect the negative battery terminal before the removal. Once the alternator is out, remove the rear cover (Three 8 mm bolts and one 10 mm bolt on a diode plare). Then with a good phillips screw driver remove the brush kit. Installation is reverse.

 

[jLB]

Just went through this on our 99 LX, although our voltage wasn’t going quite low enough to trigger the battery light. Ours turned out to be the alternator.

 

[TXLX470]

Thanks guys. Yes, it's the OEM alternator. I guess it's time to replace it, not sure how much time I do have before it gets completely bad. What's the bare minimum voltage I need to have before the engine stall?

 

[jLB]

Thanks guys. Yes, it's the OEM alternator. I guess it's time to replace it, not sure how much time I do have before it gets completely bad. What's the bare minimum voltage I need to have before the engine stall?

Our first indicator was the battery was not being fully charged, and not starting after a handful of short trips. A jump pack would start it, but it would stall/die when put in gear.

 

[213374U]

Yup, alternator on it's way out. Replace with OEM.