DANGER! install volt meter now!!
 

RUN! She's gonna blow!!

People thought my radiator had burst. I don't have a rad!
Voltage regulator went haywire...

Didn't know until it was way too late
Installing a volt meter with a warning light before driving again.

Steamed out the closed hood like a sumbich!

http://forums.pelicanparts.com/uploa...1432255883.jpg

http://forums.pelicanparts.com/uploa...1432256008.jpg

Get thee behind me malodorous odours of satanic sulpherics!

Some clever gauge updates including adding the voltmeter to the tach - recent post so have a search.

you need to get that whole trunk area wiped down with some baking soda/H20 solution asap

What he said...Inside and outside, especially if wind was blowing to rear of car..Acid will eat through paint ,clearcoat, gaskets..

You can also get a simple digital voltmeter that plugs into the cigarette lighter on Amaon for very little money that requires no additional wiring.

However, the voltmeter inside the tach does look great!

Count your blessings, could have been worse

http://i160.photobucket.com/albums/t...n/DSCF4369.jpg

Check out the brand

I had N. Hollywood put voltmeters in both the tachs in my cars for the reason you describe. The voltmeter is part of my instrument scan now. Information that you need.

I'd love to see the voltmeter in tach solution. I currently have a battery with a bad cell I think she hisses after a drive and gets quite warm.

Puddy -- I wouldn't drive your car until you both replace the battery and diagnose the charging system. A bad battery strains the charging system and a bad VR can cause the same issue as the OP

Also, my passport 9500ix radar detector has a digital voltmeter display option -- I'm now seeing my charging voltage whenever I'm NOT in a radar trap, fwiw . ..

What sort of reading would you expect to see on the gauge to predict that the battery is about to self destruct?
I've got a meter in all my air-cooled, but mostly to monitor a low charge situation. I've been stranded several times with a battery too low to crank the car.
Bill K

When my VR went duff, the alternator was putting out about 18 volt which I turn boiled the battery over.

This one work very well and is accurate. Got it AFTER i boiled the battery...

Amazon.com: INNOVA 3721 Battery and Charging System Monitor: Automotive

http://forums.pelicanparts.com/uploa...1432299708.jpg

I have one of those Amazon Volt meters in my cig lighter. lol.. never thought I would own a car where the top 2 gauges I'm constantly watching are the Oil Pressure gauge and the aftermarket Volt meter.

I guess I'm still shaking out the insecure nerves on my first-time car restoration.

Speaking of which, my alternator doesn't seem to charge until around 2000rpm+..normal? New (rebuilt) upgraded Bosch alternator and external VR. Normal?

Bill -- you'd be looking for pulses of voltage that approach or exceed 15 volts. Looks like normal charging voltage with no accessories running should be right around 14 volts (I see 14.1 when I start my car and a gradual taper down to 13.8 during mixed city/highway driving on my freshly rebuilt alternator with new VR) -- The root cause of overcharging is generally a failing voltage regulator, which will no longer control/regulate the alternator's voltage spikes.

Overcharging causes the battery acid to boil and the boil-off from the battery is hydrogen gas (same gas used to fill the Hindenburg airship).

That said, there should be a fair number of other warnings before a battery explodes. Specifically, a boiling battery emits a distinctive sulpher/rotten egg smell. When my voltage regulator first failed years ago, I was relatively clueless about this and attributed the sulfur smell to my exhaust and drove with an overcharging situation for a little while. Even though my battery didn't explode, it did leak acid into the surrounding area, requiring remediation to repair.

The pulses made my headlights and dashlights appear to dim (it was really causing them to get super bright with voltage spikes with the "dimming" effect occurring when voltage dropped back to normal). The spikes also caused a bouncy tach (which necessitated a rebuild), and random illumination of my seat belt light (I have an '86). Again, I wouldn't expect to see a sustained high voltage but, instead, frequent normal voltage with high voltage (15 volts or so) transient spikes. This makes identifying an overcharge situation more difficult without a method of constantly monitoring voltage while driving, as a spot check with a multimeter could show normal voltage at the time of the check.


Rockreid -- my '86 seems to show a lower voltage charge when driving and a higher voltage charge @ idle, so I'm not sure your situation is normal.

Bentley Manual specifies a charge rate 12.6v-14.5v... I think these numbers are a bit low.. However any charge rate over about 15.2v is a formula for for disaster, as seen in the above posts.. As stated above voltmeters can be simply installed to monitor system voltage or a more 'sexy' and fairly common modification is to have a voltmeter installed in the tachometer.. My experiences with North Hollywood Speedometer have always been excellent..
A fully charged battery at 70*F should have a terminal voltage of approximately 12.6v, with no system loading (lights, accessories, etc.).. Depending on system loading when the engine is running, the voltage should be in the stated range above..

Back when the cars were new..we replaced several wiring harnesses when the VR failed..look at your fuse-box and see if any wires have blackened/burnt insulation.

Super bright head-lamps and instrument lamps are a clue..and the seat-belt/brake warning module in the dash coming on for no good reason is always a sign of over-voltage.

FWIW -- my seat-belt warning (and brake pad wear warning) will still occasionally come on for no good reason, even though my VR is now OK. It's my understanding that by letting my original overcharging situation go unfixed for so long, I've likely damaged the warning module's circuitry. On my list to replace one day.

Yeah I agree the voltmeter in some way shape or form is a good thing to have. When my VR went haywire, I could see the voltage spikes right there on the meter- a basic analog VDO meter mounted in a bracket where the ashtray was removed. I knew something was up because the headlights were flickering a bit.

Pic of Hollywood's tach voltmeter combo:

http://forums.pelicanparts.com/uploa...1432309820.jpg

Nice!!!!