Simple Voltmeter test for VReg?
Road Warrior
Joined: Jun 2008
Posts: 1,437
Likes: 80
From: currently an Okie
Charging system
The voltage should go from 12 to about 14 volts when you start the engine if the charging system is good. If it doesn't, it could be the alternator or the regulator.
You could check for continuity of the stator with an ohm meter and then check for resistance to chassis from the stator to determine if it's the stator or the regulator that's bad if it's not charging.
You could check for continuity of the stator with an ohm meter and then check for resistance to chassis from the stator to determine if it's the stator or the regulator that's bad if it's not charging.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
output to battery must be UNDER 14.8 volts DC
NO AC voltage to battery ( bad diode in VR)
No voltage leaking back from VR to ground ( bad diode, requires ammeter).
stator output 16 to 20 volts AC ( yes, ac) per 100 rpms...so 3000 rpms should give you 45 to 60 volts AC
complete checks and specs in the electrical part of the tech forum
since you have been asking about battery- a bad battery can destroy the VR and stator....jump starting a duff battery puts a real load on the charging system- it overloads and burns up,
a $100 problem becomes a $600 problem
and a bad cable can destroy all of the above.
most multi-meters will do AC, DC, amps, and ohms functions for the tests you require
mike
NO AC voltage to battery ( bad diode in VR)
No voltage leaking back from VR to ground ( bad diode, requires ammeter).
stator output 16 to 20 volts AC ( yes, ac) per 100 rpms...so 3000 rpms should give you 45 to 60 volts AC
complete checks and specs in the electrical part of the tech forum
since you have been asking about battery- a bad battery can destroy the VR and stator....jump starting a duff battery puts a real load on the charging system- it overloads and burns up,
a $100 problem becomes a $600 problem
and a bad cable can destroy all of the above.
most multi-meters will do AC, DC, amps, and ohms functions for the tests you require
mike
Last edited by mkguitar; Sep 1, 2014 at 08:10 PM.
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Road Master
Joined: May 2009
Posts: 992
Likes: 2
From: TN
output to battery UNDER 14.8 volts DC
NO AC voltage to battery ( bad diode in VR)
No voltage leaking back from VR to ground ( bad diode, requires ammeter).
stator output 16 to 20 volts AC ( yes, ac) per 100 rpms...so 3000 rpms should give you 45 to 60 volts AC
complete checks and specs in the electrical part of the tech forum
since you have been asking about battery- a bad battery can destroy the VR and stator....jump starting a duff battery puts a real load on the charging system- it overloads and burns up,
a $100 problem becomes a $600 problem
and a bad cable can destroy all of the above.
most multi-meters will do AC, DC, amps, and ohms functions for the tests you require
mike
NO AC voltage to battery ( bad diode in VR)
No voltage leaking back from VR to ground ( bad diode, requires ammeter).
stator output 16 to 20 volts AC ( yes, ac) per 100 rpms...so 3000 rpms should give you 45 to 60 volts AC
complete checks and specs in the electrical part of the tech forum
since you have been asking about battery- a bad battery can destroy the VR and stator....jump starting a duff battery puts a real load on the charging system- it overloads and burns up,
a $100 problem becomes a $600 problem
and a bad cable can destroy all of the above.
most multi-meters will do AC, DC, amps, and ohms functions for the tests you require
mike
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