warlok

05 SE, 107k miles. My month old battery was very low on voltage, had it checked and they replaced it. Car is now running correctly but when I put a voltmeter on the battery at about 1500 rpm, it's only reading 11.89 volts (11.82 volts at idle). With a good alternator it should be about 13+, right? Bad alternator?

TDGrant

Well, maybe... But check your wires first. The connections need to be clean and tight between the alternator, battery and ground.

User1

Replace that alternator fast before you end up replacing battery #2.

warlok

Noticed a smell like burning plastic or rubber so as I would be replacing both belts with the alternator, I pulled the belt and while spinning the components by hand there was noise from the idler pulley. Replaced the pulley and both belts, didn't fix the problem so alternator is getting on order. Nissan didn't seem to be very concerned with maintenance when they designed this car. Have to pull minimum the fans, maybe the radiator, and maybe the AC compressor? That's a bit much..

TDGrant

Good opportunity to flush the coolant system and replace the hoses then. It will go pretty quick. All that stuff is easy to remove.

warlok

That's a good idea..
Any opinions on Remy, Wai Global, or TYC? All new from Rock Auto.. I read TYC makes a lot of manufacturers OEM alternators.

TDGrant

I have no idea. My thinking the guys to ask would be the ones with the sound systems since they need a good one to run their system. After that, I would focus on the warranty.

warlok

I'm gonna grab the TYC. Its 120 amp where the Remynis 110. And they are OEM for quite a few brands. Both are lifetime warranty. Thanks.

TDGrant

Sounds like a plan!

User1

Looks like we got a new bot for the wizard to zap.

TDGrant

Yes, sir!

warlok

I saw this in another thread as well. Why is the alternator so apt to take out batteries? I'm guessing that's what happened to the first battery, but how? Just because it's not charging shouldn't damage a battery.

User1

Lead acid (especially) and glass mat chemistries (these being the two most common, off-the-shelf chemistries) don't like to be repetitiously depleted to a very low state of charge then have 100 amps dumped into them very quickly to return to the SOC required by the electrical system. All battery chemistries have specific charge and discharge characteristics. Think of the battery as a voltage buffer, functioning similar to a capacitor in a circuit. Other than starting the car, the battery does very little work once the car is running. The alt supplies the power, the battery helps clean up the power, the electrical system draws from this.

When your alt begins to die, the battery is constantly being depleted and stressed at a lower SOC than it was designed for, then charged, discharged, over and over until eventually the alt dies completely, resulting in a battery that will no longer hold a charge, or now has a significantly shorter life span due to the chemistry-killing charge/discharge cycling.

warlok

Replaced alternator and flushed coolant. All good now. Thanks all.

TDGrant

Congrats!