Question for the Electrical Wizards
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Road Captain
Joined: Sep 2011
Posts: 622
Likes: 4
From: Calgary, Canada
Question for the Electrical Wizards
I have been having a starting issue with my 2010 1200 Custom after it sits more than a couple of days, even when attached to a tender.
Charging system is fine, output is 14V.
Standing charge on battery measures between 12.7-13V.
All connections at battery, starter, and ground are tight. There is no corrosion anywhere as the bike has only been in service for 9 months.
When measuring voltage while starting voltage was dropping low, sometimes as low as 7-8V. I concluded from this that the battery was bad. I installed a new battery today, and although it hasn't sat for a few days for me to know if the same issue exists, it did seem slow to turnover as it did before. If the engine needed more than one revolution to start, it probably wouldn't have started.
I am baffled. Any ideas??
Charging system is fine, output is 14V.
Standing charge on battery measures between 12.7-13V.
All connections at battery, starter, and ground are tight. There is no corrosion anywhere as the bike has only been in service for 9 months.
When measuring voltage while starting voltage was dropping low, sometimes as low as 7-8V. I concluded from this that the battery was bad. I installed a new battery today, and although it hasn't sat for a few days for me to know if the same issue exists, it did seem slow to turnover as it did before. If the engine needed more than one revolution to start, it probably wouldn't have started.
I am baffled. Any ideas??
Elite HDF Member
Joined: Apr 2012
Posts: 4,474
Likes: 2
From: Puerto Rico
The part about NEW BAT, has me baffled also... I wud do a LOAD test on these batteries, then if they pass, look to the bike, altho yur 14 charging volts should do it.
Something grounded in the starter??? Bike is 9 mos. old... ????
I don't trust the Batteries... do a load test.
Something grounded in the starter??? Bike is 9 mos. old... ????
I don't trust the Batteries... do a load test.
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Road Captain
Joined: Sep 2011
Posts: 622
Likes: 4
From: Calgary, Canada
The new battery was load tested when I picked it up, so it should be good. I'm thinking it has to have something to do with starter, although if I'm riding it alot it starts fine.
If I can't figure it out I'll have to take it to the dealer, but doing that is major PITA.
If I can't figure it out I'll have to take it to the dealer, but doing that is major PITA.
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Road Captain
Joined: Sep 2011
Posts: 622
Likes: 4
From: Calgary, Canada
I'm hoping it might be that simple, but on the bench it measured 13V...
The new battery was load tested when I picked it up, so it should be good. I'm thinking it has to have something to do with starter, although if I'm riding it alot it starts fine.
If I can't figure it out I'll have to take it to the dealer, but doing that is major PITA.
If I can't figure it out I'll have to take it to the dealer, but doing that is major PITA.
I know electronics pretty well having worked with them for 25+ years and it definitely sounds like something is drawing to much current.
Intermediate
Joined: Apr 2012
Posts: 43
Likes: 0
From: Edmonton
Know how to do voltage drops? Check out what your voltage drops are on the insulated side, the starter, and then the ground side. You should have little on the insulated and ground sides, and your starter should be sucking up all your power. If the insulated and ground sides look good then try a parasitic drain test. If you don't know how then I can easily explain.
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Road Captain
Joined: Sep 2011
Posts: 622
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From: Calgary, Canada
If I had to guess I would think the starter was drawing to much current on start up. I've had similar problems with automobiles and that's what it turned out to be.
I know electronics pretty well having worked with them for 25+ years and it definitely sounds like something is drawing to much current.
I know electronics pretty well having worked with them for 25+ years and it definitely sounds like something is drawing to much current.
Know how to do voltage drops? Check out what your voltage drops are on the insulated side, the starter, and then the ground side. You should have little on the insulated and ground sides, and your starter should be sucking up all your power. If the insulated and ground sides look good then try a parasitic drain test. If you don't know how then I can easily explain.
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Road Warrior
Joined: Oct 2007
Posts: 1,599
Likes: 11
From: Colonial Beach, Virginia
When the battery is looking at the starter it sees a direct short, the starter motor has no capability to generate counter electromotive force, so all the current the battery can make, flows. Hence the drop to as low as 6 volts while the starter is engaged. The starter motor without a load will theoretically accelerate to infinity because of that same lack of CEMF.
Something I learned in Electronics School and from articles in CycleWorld, HotRod Mechanics Illustrated and MotorTrend is that if you take a battery off the shelf and install it in your vehicle without first peak charging it, it will never achieve more 80% of its rated capacity. So it must be peaked before any leads are attached.
Something I learned in Electronics School and from articles in CycleWorld, HotRod Mechanics Illustrated and MotorTrend is that if you take a battery off the shelf and install it in your vehicle without first peak charging it, it will never achieve more 80% of its rated capacity. So it must be peaked before any leads are attached.