1990 Ultra Voltage Regulator Problem
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5th Gear
Joined: Jul 2007
Posts: 9
Likes: 0
1990 Ultra Voltage Regulator Problem
Should not the voltage regulator regulate a charge to the battery at all times?? On idle with headlight on voltage gauge reads below 10 volts, it's fine when cruising if I don't have any load on it such as sterio. Whenever I use extra power such as the sterio the voltage drops dramatically even at highway speeds. Do you think I need a new voltage regulator?? Any help would be appreciated.
Tourer
Joined: Mar 2010
Posts: 427
Likes: 1
From: Hot Springs, AR
Could be a bad/weak alternator. Seeing how the VR is cheaper and easier to replace you might try that first and hope for the best but the regulator can't help if the source (alternator) isn't working right. Take my advice with a grain of salt because I'm no mechanic.
I had a 1990 touring Harley. Good bike.
I had a 1990 touring Harley. Good bike.
Stellar HDF Member
Joined: Aug 2009
Posts: 3,212
Likes: 212
The voltage regulator just sheds of any excess voltage from the alternator so the battery doesn't get overvoltage.
If you are experiencing low battery voltage while the bike is running I would suspect the alternator first.
If you are experiencing low battery voltage while the bike is running I would suspect the alternator first.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
Jeez.
there are specific charging system test instructions on the electrical forum.
basically the alternator puts out 16 to 20 volts AC per 1000 rpms.
This AC voltage is converted to DC at the regulator, which as mentioned above sheds excess voltage regulating to below about 14.8 volts DC)
at idle your alternator is not putting out alot of voltage.
2.) the meter is the dash likely reads low, use a real voltmeter
3.) electrical tests must be made with a good charged battery, or many of the numbers will come up wrong.
4.) don't just start swapping parts with out a diagnosis of a fault ( which you probably do not have)
mike
there are specific charging system test instructions on the electrical forum.
basically the alternator puts out 16 to 20 volts AC per 1000 rpms.
This AC voltage is converted to DC at the regulator, which as mentioned above sheds excess voltage regulating to below about 14.8 volts DC)
at idle your alternator is not putting out alot of voltage.
2.) the meter is the dash likely reads low, use a real voltmeter
3.) electrical tests must be made with a good charged battery, or many of the numbers will come up wrong.
4.) don't just start swapping parts with out a diagnosis of a fault ( which you probably do not have)
mike
Road Master
Joined: Jun 2009
Posts: 1,062
Likes: 18
From: Beautiful SW Missouri Ozark Mountain Country
My volt meter reads a full volt and a half low. Take your measurement at the battery like mentioned. Also before you go buying parts you don't need, check EVERY ground wire and strap. There is a big strap from the engine to the frame underneath that gets pretty nasty. Remove it, clean it and the bolts and washers. Then take some emory cloth or some other gritty paper and clean the area of the frame and motor where it bolts to and reinstall.
Thread Starter
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5th Gear
Joined: Jul 2007
Posts: 9
Likes: 0
Could be a bad/weak alternator. Seeing how the VR is cheaper and easier to replace you might try that first and hope for the best but the regulator can't help if the source (alternator) isn't working right. Take my advice with a grain of salt because I'm no mechanic.
I had a 1990 touring Harley. Good bike.
I had a 1990 touring Harley. Good bike.
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5th Gear
Joined: Jul 2007
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Thanx Scuba; I didn't know that, I thought the reg. regulates the voltage to the battery depending on the alternator output, but what your saying makes more sense.
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Thread Starter
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5th Gear
Joined: Jul 2007
Posts: 9
Likes: 0
Jeez.
there are specific charging system test instructions on the electrical forum.
basically the alternator puts out 16 to 20 volts AC per 1000 rpms.
This AC voltage is converted to DC at the regulator, which as mentioned above sheds excess voltage regulating to below about 14.8 volts DC)
at idle your alternator is not putting out alot of voltage.
2.) the meter is the dash likely reads low, use a real voltmeter
3.) electrical tests must be made with a good charged battery, or many of the numbers will come up wrong.
4.) don't just start swapping parts with out a diagnosis of a fault ( which you probably do not have)
mike
there are specific charging system test instructions on the electrical forum.
basically the alternator puts out 16 to 20 volts AC per 1000 rpms.
This AC voltage is converted to DC at the regulator, which as mentioned above sheds excess voltage regulating to below about 14.8 volts DC)
at idle your alternator is not putting out alot of voltage.
2.) the meter is the dash likely reads low, use a real voltmeter
3.) electrical tests must be made with a good charged battery, or many of the numbers will come up wrong.
4.) don't just start swapping parts with out a diagnosis of a fault ( which you probably do not have)
mike
Thread Starter
|
5th Gear
Joined: Jul 2007
Posts: 9
Likes: 0
My volt meter reads a full volt and a half low. Take your measurement at the battery like mentioned. Also before you go buying parts you don't need, check EVERY ground wire and strap. There is a big strap from the engine to the frame underneath that gets pretty nasty. Remove it, clean it and the bolts and washers. Then take some emory cloth or some other gritty paper and clean the area of the frame and motor where it bolts to and reinstall.
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