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MG MGB Technical - voltage stabiliser

I keep suffering from a failed voltage stabiliser on my V8. i have the origianl bi metallac strip type in place which I am told will fail quickly i the car is laid up/ not used much. Apparantly when you start the car after a lie up the battery takes a fairly heavy ampage in order to charge up again. Thsi adversally affects the old voltage stabiliser and can cause early failure. i seem to have to change mine every 18 months or less.
Solution is to get a more modern transistor type . Any oen any ideas or reccomendations on this . if so where can I get one
thanks
brian
Brian

Brian,
Though I have a generator in my "A", but along with you the car may sit for some time, maybe a month or two in the winter. To avoid heavy charging at initial start up, I pre-charge the battery with a small trickle charger. This avoids the heavy charge to the battery upon start-up and for me it reduces the heavy load on the generator.
This "pre-charge" may prevent your voltage stabiliser switch from failing. Just my two cents worth.

Ray
Ray Ammeter

Brian,

Contact Wray Lemke at WrayLemke@compuserve.com for one of his solid state stabilizers. Tell him 'Eddie Petty' sent ya'

Ed in 'ole Virginny
Eddie Petty

There is some confusion here.

The voltage stabiliser is indeed a bimetal strip on the firewall inside the cabin but only powers the fuel gauge. Layups, flat batteries and the like will have no effect on it, but a partial short or incorrect wiring will damage it.

The alternator has an internal electronic voltage regulator, and a layup or flat battery will cause the alternator to put out a greater current on restart, but that shouldn't damage the voltage regulator, however other defects in the alt or wiring could.

Which are you having problems with, instruments or alternator?
Paul Hunt

paul
The voltage stabiliser keeps failing. It powers my fuel gauge and voltmeter on the dash. It has just been replaced by an auto electrician who checked out the rest of the wiring and alternator..all OK. Apparantly it is a common failure for these old bimetallic regulators. Unless i can find a solid state one i guess i will have to keep replacing it every 18 months or so
brian marshall

OK, nothing to do with laying up and flat batteries then. Mine have been running for at least the 11 years and 7 years I have had the cars, the first is a fine weather car the other a daily driver. There is nothing intrinsically wrong with the instrument voltage stabilisers, you must have some other problem causing them to fail, like a partial short on the output as I mentioned.

The stabiliser should NOT be supplying a voltmeter for obvious reasons. If it is, and working correctly, the voltmeter will be going up and down, or a thermal gauge might show about 10v instead of the normal running voltage of about 14v. On the other hand it may be that the voltmeter is simply picking up its supply from the green wire on the *input* to the stabiliser, hence is not being fed *by* it. Is the stabiliser screwed to the bulkhead and making a good ground connection? It should be. You can check this by connecting an analogue multi-meter to the output of the stabiliser, the light-green/green, and it should show voltage switching on and off once or twice a second.
Paul Hunt

Brian

Check the B archives, both General and Technical, and search on voltage stabiliser. There is a thread in each on this topic, and a link to a supplier of new units.

Larry
Lawrence Hallanger

This thread was discussed between 28/01/2002 and 30/01/2002

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.