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Solving weird digital volt meter

Posted: Sat Aug 15, 2015 8:39 am
by sagaboy
I have installed a new high end accurate digital volt meter and experience it automatically getting shut down by itself after a few minutes so much so that I have to installed a toggle switch to turn it on and off whenever I need to have a look at the state of voltage while driving but it worked perfectly well when the engine is not running.

After a month of this annoying problem, it dawn on me that perhaps the running engine alternator supply voltage must be having some "spike" that causes the problem and I decide to add an additional diode hooked up with an additional 2,000uf capacitor to the diode circuit from the 12v power line to the digital volt meter -- it worked great, no more auto shut down BUT the diode causes a 1.5v voltage drop and the digital meter will display the current voltage minus 1.5 volt and not being happy with it....

I decide to remove the diode and simply connect the 2,000uf capacitor (one end to ground) and the other end to the +12 supply to the digital volt meter -- poof... worked great, end of auto shut down and no voltage drop.

Re: Solving weird digital volt meter

Posted: Wed Aug 26, 2015 7:18 am
by Dale M.
Sound to me like your high end digital meter has a problem, I would go back and whine at manufacturer of product...

Dale