pweishaupt

my beltronic is giving me a high voltage alert (goes off if it hits over 16.5) it is intermitten. does this mean i need a new voltage regulator? (bentley manual says possible for 'over charging'?' (it's the 88 targa)

irobertson

I would first meter it with a digital volt meter, but yes, if it is measuring that high you will need a new VR.
I did mine last year. I was reading 18.5V and boiling my battery dry. The battery was swollen from the pressure and had cracked. I also converted to an Optima battery so if it ever happened again I wouldn't risk acid leaking in my trunk.

pweishaupt

whats weird is that it is intermitten. someone else on another board said i would need a new alternator.. think i'll start with the vr...

dshepp806

I ended up changing both out at the same time,..they were both found to be the original equipment (20 years old!)

Best!

Doyle

dshepp806

I would say, as well, that I was made aware of this intermittent OV condition via my Passport! Cool,..I've yet to put a meter into the car but certainly have ALWAYS used the detector voltage monitoring feature.

Just a suggestion: do check the voltage AT the Battery Posts and compare to where you're monitoring the voltage (cig lighter obviously)...sometimes there can be a voltage drop at the the cig lighter,...you want to know what's happening AT the frikin Battery...

COOL!

BEST!

Doyle

rusnak

Usually a new alternator comes with a new voltage regulator.

Get out the multimeter!

Lorenfb

"(goes off if it hits over 16.5) it is intermittent"

Common problem!

"Usually a new alternator comes with a new voltage regulator."

Obviously if it's a new one. But many Bosch/rebuilds come with a used
regulator which was just tested and the brushes were replaced.

"Get out the multimeter!"

Can't always test for intermittents!

wwest

An intermittent connection, or a "high" resistance connection, in this case in the milliohm range, can result in the alternator putting out "high" voltages, especially voltage "spikes" that do not ovecharge the battery but still have an adverse effect on solid state electronics such as the tach, rev limiter, cdi, etc.

Clean and burnish the battery posts and connection contact area and the same for the alternator "feed" at the starter motor.

rusnak

That's good advice. 3.2s are notorious for corroding the battery clamps.

pweishaupt

thanks all. i'll try to get to it this weekend...

vracer

Having read "all the books" prior to buying my '89, I learned that this is common for the 3.2s. It happened to me driving my 20K mile car home. The first money I had to spend on the car was for alt./vr.
The radar detector sounds like a great 'multi-use' tool.

dshepp806

SO TRUE! I've used lotsa' instrumentation in my days (on the bench),..mostly with storage scopes,..but always on something I can SIT on the work bench,..never something mechanical like an engine.....(alt/VR intermittent schemes....)

My case was exactly like yours'...one day, my Passport reported high voltage (keep it in that mode, plugged into the cig lighter to monitor vlotage) then went back to normal voltage(s). In the early days of this arrangement, I was sure to check battery voltage AT THE TERMINALS,..to compare to the cig test point,..allowing for the (decimal) difference. I still check it to see that all is well...usually, vibration will loosen the connection (at worst) causing erroneous readings...ANYWAY,..the OV concerned me.....nothing looked awry as to battery levels, charge voltage, etc....but I didn't "go surgical" and remove the alt, have a look at it's brushes, etc,.. nor study the VR components,...not check the diodes,.....not look at any of these electrical connections. Decided I'd wait and look for another event repeat,..sure enough,..the VERY NEXT day,..it happened again (exactly the same).....end of playing around,..envisioning my DME rx'g FAR more voltage than it's looking for (so to speak), for ANY duration....took the car to my P-wrench,...shared the events,..then told him to install a NEW alt/VR and verify the battery (period)...No testing requirement required,...just do it.

No problems since,.......he extracted THE ORIGINAL ALT/VR from my 1989! Pretty frikin' amazing,..talk about preventive maintenance? SHEEEIT,..one needs to keep the electrical components fresh,..in anything....

Since then, there have been several threads where there's been discussion of over-voltage protect circuits, primarily thru the DME relay....it was Loren who actually provided a schematic of a circuit that would do just fine,..other contributions from WhaleBird regarding Mercedes' approach,...yaddiyaddajaddi......... good reads , preventively-speaking....i fully plan to implement this approach...

AT MINIMUM: to protect the DME...BTW, thanks, Loren for your input on that discussion..........good sheeit....