my lights are dimming when i stop. my passport 8500 shows upper 13s for voltage while driving and right about 12 when stopped IF i put the car in neutral (A4) if i put/leave it in any drive gear the voltage drops to mid-low 11 volts.....whats up or is it normal? other day on the interstate in a backup i had to turn my fog lights off, defrost off, etc becasue i was low on power, my radar detector wouldnt stay on and 2 speakers were cutting out if in gear and in and out when in neutral.....

 

Sounds like it's time to get your battery load tested.

 

can autozone do that? i know they can test some stuff

 

Around here AZ does it free. When my car started doing the same thing I ignored it and soon after my battery went completely dead. No other warning, car always started fine - then one morning even my keyless entry wouldn't work.

 

i'll get it checked asap....what was your problem if you dont mind me asking

 

It was the battery - summer time and at lights with the AC on, in gear, volt gauge would drop below 13, sometimes almost into the red. Had 30 months on my stock AC delco - when I couldn't unlock the doors with my remote had to use the key - popped the hood and the green eye was dark. Your problem is probably the same since you're getting high 13's from the alt. My in gear idle is set higher than stock too.

 

How old is your present battery?Is it completly sealed battery?What condition are the battery cables/connections in?Have you checked your body/engine grounds?Have you checked voltage at the battery with the car running and off(running you should have between 12.5vdc to 14.3vdc and not running it should be no lower than 11.9vdc).Autozone will check both your battery and alternator output for free.And with colder weather your really taxing the battery to start the car.I recently bought an Optima red top for my Jimmy because my old battery started leaking and of course was just out of free replacement warranty so it was a good time to upgrade.

 

I just had to replace my battery. I bought it in March 05 and had to have it replaced this Monday. Sad thing is the battery in my truck didn't last one year and I had to have it replace too. I say its Advance Auto junk.(FYI, I have factory radio's and nothing drawing more juice) I bought the Titianium batteries from them and thats two that has went out in less than a year. I've started buying my parts from Auto Zone lately. It's a little bit of a drive compared to Advance but considering their quality as of late I don't mind.

 

I went thru the same with battery's from Walmart in my Jimmy.Every year I find go out to find a dead battery.I switched to an Optima Redtop and haven't had any problems yet(battery is only 6 months old though)

 

I got a question. cold or warm when my car is idleing at night and i tap the gas to rev it up, when the RPMs drop back down to idleing speed all my lights dim out for 1/4 second. headlights, instruments, cdplayer, everything. and its everytime the rpms drop back down after a rev. Why? why why?

thankSS

 

mine stay dim adn idle is like 700 but if i keep it right bout 1000-1100 the volts get high enough to keep everything ok

 

The SI alternators have what's called an excitor that is rpm sensitive.The outputs the alt rated are at taken at something like 1200 to 1800 RPM,I don't remember exactly.If you have a weak link like older battery cables or a loose engine/body grounds it becomes noticeable at idle,especially at night.Electrical cables age with use due to the duty cycle of heating/cooling when the car is running.Add in the harsh enviroment they live in too.I've replaced/upgraded the battery cables on my Jimmy and my idle output doesn't drop off as noticably.