Up front, I wanna apologize if anything I ask here has already been answered. I'm still kinda new

I left my 06 RL parked for a week and a half when I went home for Thanksgiving. Came back to a dead battery.

Crap.

Charged it back up with my battery tender, swung over to the parts store to get the battery checked out. They said the battery is good, but my alternator was reading low, 13.5 volts. I'm not getting a charging system indicator light.

Two Questions:

1. Is 13.5 volts actually low for the alternator at idle?
2. Can I trust that the charging system indicator will tell me if the alternator starts failing?

Thanks y'all!

 

was it ever been replaced or is it still the original?
does it make whining sound?

you'll know when to replace as alternator will start whine and your dash will lit up like christmas tree.
charging system failure, sh-awd failure, afs failure, navi will say turn off excess accessories, etc

your battery shouldn't be dead over few days/weekend.
sounds like you have short somewhere. door lock/unlock sensor on passenger side is well known to be source of problem, especially if it's wet.

 

I'll have to check the records I got from the previous owner, I don't know if it's been replaced. There is a slight whine coming from the left side of the engine, but it's really faint.

Yeah, I figured that was a short time for it to go dead. Any tips on looking for parasitic drain?

 

Blue tooth units have been known to go bad and drain batteries, same with door handles. Get a meter and start pulling fuses. Google how to find a parasitic draw, you tube has good videos. Helpful and much faster to have two people do it. 13.5 should be enough to charge your battery.

 

Did you pop your trunk via the door button before leaving it? Known bug in early model RLs.

 

For me, my Bluetooth started to sound very bad (almost a bad connection) for about a week, then my steering wheel wouldn't go forward when the car was shut off.

Then a slight whine from the Alternator (for about 10 min) and then boom... Christmas tree.

Everything went back to normal after the Alt replacement.

A bad battery gave me the same signs about 2 years once before (minus the Alt whine).

 

Is the new one upgraded version or is it basically the same one with the same problems?

 

With car running alternator should be reading 14.5 so it is a bit low. But if you're still holding charge and don't see any further problems you can leave it, but if you want a peace of mind then change it.

A somewhat common issue is the alternator whining, it still holds charge but just the bearing is shot