Any expert on battery and alternator issue? Please give opinion.

[rnln]

The acid smell... today.
On the way home from a friend mechanic shop to take care of the yellow ignition wire, I smell the acid smell. I thought to myself, can't be battery. My battery has been so good to me all the time. Maybe the oil leak and burn at the exhaust? Can't be oil burn since I am driving and the oil/exhaust is behind me. The more I drive, the stronger the smell was. When I got home, I smell the engine bay and below it, can't smell the oil at all. Everything is normal. When I look at the battery, it look normal. I even get the flash light out to look around it carefully (it's not dark yet). The whole area is dry and very normal. When I got my nose very closed to the batery, 2" closed, I can feel slight acid smell but the battery look very normal and dry. Probably when I am driving, reving the car, the smell come out stronger?

I then got the voltage meter out and measure across the battery poles. At engine shut off, I got around 13+V. At idle, I the V is jumping between 15.50v to 16.30v.
I came out at night, started the engine, rev it to 2.5kRPM and measure the voltage. Now it is at 14.3v steady when idle.

Summary:
Strong acid smell when driving. Battery look dry and perfectly normal.
Engine shut off, V between battery poles is 13+V, less than 14V.
Engine idle, V is jumping between 15.5V to 16.3V.
3 hours later, idling at 14.3v
Is it just the battery is about to go bad or is it the alternator? Or just the voltage regulator?

In the past, I used to guess it's the battery anyway. If still problem, I go to the alternator. Now I don't want to just guess anymore since if I replace the battery and if it's the alternator problem, then the alternator will kill the new battery again. Then I have to replace both (alternator and battery again). Also because I got you guys, the expert here.

Anyone know what is the exact problem? Or know how to troubleshoot this?

Now I know a good reason to install an indash voltage meter.

Thanks in advance.

[LakeCleElum]

Too much voltage at idle......I think your regulator is about to toast your good battery....

[Chris Holcombe]

Bad voltage regulator. Voltage should be mid 14s. The 15-16 volts you're getting is boiling the battery and making the acid smell. Bad regulators are a common problem on SCs and Carreras

[oneblueyedog]

I agree with the bad VR diagnosis. A bad VR will also eventually overheat the diodes in the alternator. My rectifier bridge (diode pack) went out as a result of limping home with an overcharging VR.

[911 Rod]

Other symptoms (regulator) are flickering head lights and seat belt warning light.
I replaced the battery, alternator and regulator and everything works great.
And yes I now have a volt meter mounted in the car no matter how ugly it is.
WTF is with the flashing seatbelt light? Is this a German version of an idiot light?

[rnln]

Thanks guys.

911 Rod,
You just choose to repalce all battery, alternator, and regulator at the same time?
umm.. I rather replace one if I know what it is. Let try the VR first, since it is the one most people suspect.

Anyone know the steps of taking thing apart to get to the VR?

Thanks.

[Wil Ferch]

This has been posted numerous times before, as well as being listed ( with other topics)...in the "Tech info center" ( see tab option on top of this posting)

---> http://www.pelicanparts.com/techarticles/911_volt_reg_replace/911_volt_reg_replace.htm

- Wil

[rnln]

thanks much Wil.

[911 Rod]

Originally posted by rnln
Thanks guys.

911 Rod,
You just choose to replace all battery, alternator, and regulator at the same time?
umm.. I rather replace one if I know what it is. Let try the VR first,

Thanks.

Ya, I was on a roll.

Coming back from a long trip, I boiled over my battery because the regulator gave up. The place I took it in to for a rebuild insisted on re-coiling the alternator because of the high voltage going through it because of the faulty alternator.

This was a really bad boil over as there was acid dripping of of the inside of the hood.

Should have called a flat bed but I had to pick up my daughter and she comes first.

BTW When they bench tested the alternator/regulator it was fine.

[rnln]

"bench test and both alt and VR were fine". Intermediate problem huh. I feel mine is the same now. Problem was that bad, but couple hours later, it was gone.

[rnln]

Update...

As what I first decribed, high voltage on battery poles, no doubt everyone will point right at the Voltage Regulator. Because I said the battery looks perfectly clean.

I plan to slowly taking off nuts and bolts one by one every day I get home after work but I get so lazy. Every time I got to the car, I hold my coffee cup and a garette, or start the engine and walk around the car touching it here and there until it's dark. Several times I let the engine run for proximately 1/2 hour or so, idling, reving slowly, etc... and the voltage got to max around 14.5v without any instrument turned on.

Today, I actually open up the hood and take the negative cable off the battery. Because I was too lazy to "work", I opened up the battery caps to see how it's in there. oups... I found something which it should be the first thing to check... there is no more water/acid in there.

This doesn't mean I solve the problem right? Because there still is a possibility that the battery ran out of water the same time the VR got damage. But there is a 50% chance that the battery is dried, and everything else is still good. Am I correct?

Now a new question I have. Long time ago in the old time, we use to go out there and get the distill water or acid to pour in the battery. Later on, I found that no place is selling distill water any more. There only place I know is still selling acid is the motobike shop but their price is not that nice.
Anyone know any solution on distill water/acid?

Thanks.

[LakeCleElum]

Your battery is dry because it was overcharged (due to a bad VR) and boiled all the fluid out of it.

I used bottled water in a battery, it has very few minerals in it...

[Nashville84Cab]

I was experiencing a very similar problem in that my battery was fried. I got a new battery and everything is back to normal except that my lights go from bright to dimm during normal night time driving. I took it up to get the alternator checked out and it checked out perfect. When I had them check the voltage during normal to high revs, they said my voltage readings was 18V. Way to high! They told me that I need a new regulator. So I am about to purchase one and hope to install it myself. And I have used bottled or filtered water to fill my battery with no problems (which is the same as distilled water if I'm not mistaken). You can probably get deionized (DI) water (hospitals or research labs), but I think that would be unnecessary. Good luck.

[911 Rod]

There are many types of bottled water. Don't go there.
You can buy "distilled" water at any Pharmacy by the gallon.
IMO Not doing all 3 variables is just asking for trouble.
The old "while you're in there" scenario definitely applies here.

[Wil Ferch]

You may also have another problem....acid or acid/water seepage under the battery in the tray area.... very bad. Get it cleaned up with baking soda and a good water rinse, and apply some paint or protectant there afterwards...

Silly Porche designers...the acid will eat right through to the front suspension pivot ( think that might be important?)...and all the "nearby" copper contacts of the electrical fusebox should be checked too...

If you replace the battery with another "conventional" one, get one with a little male vent on the battery case so you can attach vinyl tubing and bring it "outside". Otherwise , get a sealed type battery like a Stinger or an Optima.

- Wil

[911 Rod]

Originally posted by Wil Ferch


If you replace the battery with another "conventional" one, get one with a little male vent on the battery case so you can attach vinyl tubing and bring it "outside". Otherwise , get a sealed type battery like a Stinger or an Optima.

- Wil

My new battery has the vent tube, but I did not take it "outside" for fear of it blowing on to tire etc.
I chose a volt meter instead.

[rnln]

Thanks guys,
A trip to Walgreen tonight, the phamarcy it is.

[goldgunner]

WIth all the voltage regulator problems, it should be worth considering the K3 with internal regulator. Pricey but new technology all the way.
http://www.k3.com.au/

Eventually when my rebuild is complete, I'll find out if the K3 - among a zillion other things - does the job. But, I expect the K3 not to be an issue...

[Wil Ferch]

If you have a vent tube...and you don't vent it outside...what's the point?

Make it long enough and get it away from stuff !! .... venting *somewhere else* inside the car doesn't accomplish much....

Doesn't have to overcharge to vent , either....regular lead-acid batteries "breathe" under "normal" operating conditions....

- Wil