Voltage Regulator HELP

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Oct 15, 2011 | 09:59 AM

trackadaptor

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Road Warrior

Joined: Apr 2007

Posts: 1,406

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From: Sunnyvale, Ca.

Voltage Regulator HELP

Voltage Regulator: 2009 FLHTCU 33k miles.... New Battery , Load Test is OK

So what are the signs the Voltage Regulator is going bad ?

Or do you have to wait till it just stops working ?

Symtoms: Start up Volts sit at 10.5 - 12.5 issh - start to ride goes to 14.3

Come to stop light: drops to 13.0 isssh then moves up to 14.0 then sometime drops to 12.0

Oct 15, 2011 | 10:04 AM

dawg

Seasoned HDF Member

Joined: Jun 2006

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From: Vermont

Don't trust the gauge alone, take true voltage readings.

Oct 15, 2011 | 10:16 AM

Stiggy

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From: Oxford, Nc

At idle mine's under 12 Volts. The only thing I watch for is a consistent 13.5 volts at 2000 rpm and above. No wavering needle, no varying voltage, just 13.5 Volts

Oct 15, 2011 | 10:17 AM

rushbass

Ultimate HDF Member

Joined: Feb 2010

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From: Biloxi, MS

I had an intermittent low voltage problem - the volt meter would drop below 12vdc, and the CEL would come on and throw a P0562 DTC (no other codes present)... it would stay in the low voltage condition and come out after @ 1 minute... this would happen regularly...

turned out to be the voltage regulator. Good luck with your troubleshooting.

Oct 15, 2011 | 11:52 AM

cooper57M

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At idle my bike always read 14 volts. Never goes under that

Oct 15, 2011 | 11:59 AM

mkguitar

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From: Phoenix '53, '88, '09 Big Twins

those readings as described seem normal.

bad regulator may display any or all of these:

allow voltage above 14.8 VDC to reach the battery ( damaging the battery)

allow AC volts to pass through

allow power from the battery to drain when bike is not running

-----------------------------------------

the alternator produces about 16 to 20 volts AC per 1000 rpms.

the regulator converts that voltage ( could be over 100 volts AC) to DC and "regulates" to less than about 14.8 volts DC.

the voltmeter in the dash, is not tremendously accurate, but can give an indication of function-- if you see it reading way high or way low, then further investigation is needed.

but readings taken with a real voltmeter at the battery and alternator plug are needed for real charging system diagnosis-- again, if a problem exists.

mike

Last edited by mkguitar; Oct 15, 2011 at 03:02 PM.