Low Voltage when on the brakes.
Thread Starter
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Intermediate
Joined: Apr 2011
Posts: 36
Likes: 0
From: PA
Low Voltage when on the brakes.
My 03 ultra is acting funny. When ever I apply my brakes and hold them" like at a stop light", I can watch my volt meter slowly drop. goes from 14.2v down to about 10.5 or 11v depending on the duration.
Seems like my charging system is overloading. my idol rpm is around 1050. the bike is fuel injected, and I do not have any extra lights or accessories, that are not stock.
Is this a sign of a bad battery ? the bike starts fine. I have checked all my brake wire connections, they seem good.
Any other ideas
Thanks
Seems like my charging system is overloading. my idol rpm is around 1050. the bike is fuel injected, and I do not have any extra lights or accessories, that are not stock.
Is this a sign of a bad battery ? the bike starts fine. I have checked all my brake wire connections, they seem good.
Any other ideas
Thanks
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
Likes: 402
From: Phoenix '53, '88, '09 Big Twins
to test the battery
it has to be fully charged ( with a 'real" charger, not a trickle charger like a tender)
autozone will load test for free
a battery that is on it's way out can overload/ stress the charging system, taking out the regulator
so do a couple of checks when you can, to avoid any damage and for piece of mind.
if battery/charging system are all fine, then we need to chack and see if there is a problem in the brake light circuit ( such as lowered bikes sometime the tire rubs through the insulation on the wires, allowing the voltage to ground through the dirt of the inside of the rear fender- there are other potential areas of fault as well.
mike
it has to be fully charged ( with a 'real" charger, not a trickle charger like a tender)
autozone will load test for free
a battery that is on it's way out can overload/ stress the charging system, taking out the regulator
so do a couple of checks when you can, to avoid any damage and for piece of mind.
if battery/charging system are all fine, then we need to chack and see if there is a problem in the brake light circuit ( such as lowered bikes sometime the tire rubs through the insulation on the wires, allowing the voltage to ground through the dirt of the inside of the rear fender- there are other potential areas of fault as well.
mike
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
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From: Phoenix '53, '88, '09 Big Twins
Seems that Deka batteries are same manufacture as H-D. so similar AGM quality with out some of the cost.
to check rear wiring for problems, simply unplug the connector for the rear lighting under the seat- if your brake is pressed at the time - the volt meter would jump right up.
BTW the in dash voltmeter is not the best and truest- it suffers from voltage drop in the main harness.
In my 1995 is was 1.6 VDC low ( until I did some re-wiring), on my 2009 is reads about .7 VDC low-
Measurements for diagnosis best made with a voltmeter at the battery terminals
mike
to check rear wiring for problems, simply unplug the connector for the rear lighting under the seat- if your brake is pressed at the time - the volt meter would jump right up.
BTW the in dash voltmeter is not the best and truest- it suffers from voltage drop in the main harness.
In my 1995 is was 1.6 VDC low ( until I did some re-wiring), on my 2009 is reads about .7 VDC low-
Measurements for diagnosis best made with a voltmeter at the battery terminals
mike
Last edited by mkguitar; Aug 14, 2011 at 12:50 PM.
Outstanding HDF Member
Joined: Dec 2007
Posts: 2,803
Likes: 11
From: El Paso, Texas
Seems that Deka batteries are same manufacture as H-D. so similar AGM quality with out some of the cost.
to check rear wiring for problems, simply unplug the connector for the rear lighting under the seat- if your brake is pressed at the time - the volt meter would jump right up.
BTW the in dash voltmeter is not the best and truest- it suffers from voltage drop in the main harness.
In my 1995 is was 1.6 VDC low ( until I did some re-wiring), on my 2009 is reads about .7 VDC low-
Measurements for diagnosis best made with a voltmeter at the battery terminals
mike
to check rear wiring for problems, simply unplug the connector for the rear lighting under the seat- if your brake is pressed at the time - the volt meter would jump right up.
BTW the in dash voltmeter is not the best and truest- it suffers from voltage drop in the main harness.
In my 1995 is was 1.6 VDC low ( until I did some re-wiring), on my 2009 is reads about .7 VDC low-
Measurements for diagnosis best made with a voltmeter at the battery terminals
mike
Last edited by Dionicio; Aug 14, 2011 at 01:06 PM.
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From: Nevada
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From: Oxford, Nc
Fuster, My bike has been doing that since new....12 years and 92,000 miles ago.
Its the 14.2 volts at 2,000 rpm and up that counts.
Its the 14.2 volts at 2,000 rpm and up that counts.
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Thread Starter
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Intermediate
Joined: Apr 2011
Posts: 36
Likes: 0
From: PA
So what I am seeing may be considered normal, on my model year bike. Does seem strange that the load of three bulbs turning on is enough to move a meter.
I would think the stereo would pull more when the volume is turned up.
I would think the stereo would pull more when the volume is turned up.
Extreme HDF Member
Joined: Sep 2010
Posts: 14,744
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From: Phoenix '53, '88, '09 Big Twins
turning electricity into incandescent light takes more power than you'd guess ( esp. compared to solid state radio).
on a 12 volt system, 100 watts of light equals 8.3 amp current draw.
you can add up the watts and calculate the current draw.
mike
on a 12 volt system, 100 watts of light equals 8.3 amp current draw.
you can add up the watts and calculate the current draw.
mike