Is it normal for the voltmeter to drop from 13-14 volts to 11-12 if running the a/c and headlights? If not, is the battery or the alternator suspect? How hard is it to tighten the alternator belt on this car?

I'm a 996TT noob, but I did search first.

Thanks,
Chris

 

It is normal to see the voltage meter drop slightly when you turn on a high amperage device such as lights or air conditioner. The needle should move back to where it was soon after the drop and the device is fully operating. If it does not, it is probably your battery. You cannot adjust the belt, but take a look at it to make sure it looks in good condition. It could be, but is unlikely that the alternator or regulator is bad, as these devoces seldom have problems. How old is your battery.

 

Thanks for the info. On closer inspection, the voltmeter only drops to 13v, and this is only at idle with accessories on. At higher rpms it returns to a hair under 14v.

I do not know how old the battery is as I've had the car less than 1 month. It does not hav ethe oem battery...it's an Interstate.

 

My car does the same thing, and I have a brand new beefed up Interstate battery. If I have the A/C on and stereo blasting (not stock) it's noticeably lower than when these items are on. The amp for my stereo is not humungous or anything so I don't know ...

 

It is normal for the volts to drop to 13.x at idle with the AC and headlights on.

 

With my a/c on high and headlights on my voltage was just over 12 at idle. The 2 radiator fans and the interior fan pull a lot of current.

 

raise the revs just over idle, it should run at 13.5 to 14.0 with low load, and will drop with increasing load. However fully loaded you would want to see no less than 12.5V, and in no circumstance should it ever run above 14, nor below 12.5V. Average ambient temp.

 

Thanks for the responses!