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Discussion Starter · #1 ·
About a week ago I had been riding for about an hour and stopped at a store for a few minutes. When I came out and turned the key - nothing, no sound, no instrument lights, no reaction to starter off course. I trailered the bike home and found that the battery voltage was about 6V.

Since the battery is only 1 year old I charged it up and took it to an auto parts store where they did a load test and said the battery was fine. They did seem to take some care as we had to look up the cold cranking amps to set the tester.

Put the battery back in and I'm getting about 12.5v with key off and about 13.7 when running (at the battery terminals). I checked the stator output and it is correct per the manual.

Ducati manual says that charging voltage at the battery should be 14 to 15V.

So does anyone else tend to run at about 13.7 V without problems? My son who is an electrical engineer thinks that its some kind of intermittent battery failure.

I haven't ridden the bike since the incident but it starts up fine and the battery seems to be maintaining voltage like normal.

Any thoughts would be welcome.

2007 ST3
 

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Premium Member
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5,700 Posts
Is that 13.7VDC at idle or say about 4K RPMs? There have been problems with voltage regulators going bad. I wouldn't discount the possibility. Did you check the connector @ the 3 yellow wires for melting and or corrosion? I think I'd suspect a faulty regulator before a newish (brand name???) AGM battery that passed a load test, but it really could be either.
 

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Mr Leakered
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Yes. My voltmeter typically shows 13.4v to 13.8v while riding. The battery voltage is consistently high when sitting.

Have a good one.
 

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Discussion Starter · #4 ·
SS904

13.7 from idle on up. All the connections look perfect. I'm wondering if regulators sometimes drop out intermittantly. I may try riding with my multimeter hooked up and observe the voltage.
 

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Old Wizard
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If you use an on-board voltmeter, if the regulator has been previously heat damaged, you will see a normal high-13 volt battery voltage upon startup and initial running but it will later drop to under 12 volts after the regulator heats up. Ride long enough and you'll obviously deplete the battery. After cool-down the cycle will repeat itself until the regulator eventually fails. Moving it to a cooler location will sometimes save the regulator.
 
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