Electrical while cranking

[in2it]

I'm helping a friend with his 1500... on his 1500 ... with me on a meter connected to the battery.... the electrical power to the battery would plunge to zero ... and then suddenly the power would return ... while trying to crank ... also with the meter connected to the dog-bone fuse and the rpm is 2500 the power to the dog-bone is 10.53 to 11.15 ... has anyone ever had this problem??? ... and all of this has just started

[MikeB]

I have never seen this. But, if I had, I would remove the bolts and wires from all the connections between the battery and dog bone fuses, clean with a stainless brush and some solvent and then reassemble and test again.

[4given]

What Mike said. You are probably going to find either a loose connection or corroded terminals somewhere.

[WingAdmin]

Don't overlook the battery itself. They can develop cracks and other faults internally that can cause power to intermittently disappear.

[in2it]

***UPDATE*** I started with a fully charged battery ...the battery was out of the battery box and sitting on a 2X6 ... the reading I got on a full charge was 13.77 after a hour sitting on the bench the reading was 12.87 ... the Solenoid A looked good no burn spots ... while the bike was running and the RPM were above 2000 the read on the lower screw on the dog-bone was 12.55 ... what baffles me is the way it lost current just sitting on the bench ...the battery is a gel type of battery and was bought a few months ago

[WingAdmin]

***UPDATE*** I started with a fully charged battery ...the battery was out of the battery box and sitting on a 2X6 ... the reading I got on a full charge was 13.77 after a hour sitting on the bench the reading was 12.87 ... the Solenoid A looked good no burn spots ... while the bike was running and the RPM were above 2000 the read on the lower screw on the dog-bone was 12.55 ... what baffles me is the way it lost current just sitting on the bench ...the battery is a gel type of battery and was bought a few months ago

It's normal for a battery voltage to drop immediately after charge. 13.8 is the voltage you will see when the battery is either charging or on a float charge. For an AGM gel cell battery, 12.8 volts is 100% state of charge, so the battery was fully charged.

When the bike is running and above 2000 RPM, you should see 13.8 volts (or thereabout) on the battery terminals. If you are running the bike and seeing only 12.5, that indicates that the alternator is not charging the battery. So it's possible that the old battery was bad because the alternator isn't functioning.

[in2it]

***UPDATE*** I started with a fully charged battery ...the battery was out of the battery box and sitting on a 2X6 ... the reading I got on a full charge was 13.77 after a hour sitting on the bench the reading was 12.87 ... the Solenoid A looked good no burn spots ... while the bike was running and the RPM were above 2000 the read on the lower screw on the dog-bone was 12.55 ... what baffles me is the way it lost current just sitting on the bench ...the battery is a gel type of battery and was bought a few months ago

It's normal for a battery voltage to drop immediately after charge. 13.8 is the voltage you will see when the battery is either charging or on a float charge. For an AGM gel cell battery, 12.8 volts is 100% state of charge, so the battery was fully charged.

When the bike is running and above 2000 RPM, you should see 13.8 volts (or thereabout) on the battery terminals. If you are running the bike and seeing only 12.5, that indicates that the alternator is not charging the battery. So it's possible that the old battery was bad because the alternator isn't functioning.

I went after reading your reply and disconnected the terminal from the alternator to the lower dog-bone screw ... cranked the 1500 and wasnt getting anything from the alternator at 2000+ rpm's .... I then put the terminal back on the dog-bone and cranked the 1500 ... it showed 12.55 ... so the battery was back feeding through the dog-bone ... so now it's alternator time in my opinion

[WingAdmin]

***UPDATE*** I started with a fully charged battery ...the battery was out of the battery box and sitting on a 2X6 ... the reading I got on a full charge was 13.77 after a hour sitting on the bench the reading was 12.87 ... the Solenoid A looked good no burn spots ... while the bike was running and the RPM were above 2000 the read on the lower screw on the dog-bone was 12.55 ... what baffles me is the way it lost current just sitting on the bench ...the battery is a gel type of battery and was bought a few months ago

It's normal for a battery voltage to drop immediately after charge. 13.8 is the voltage you will see when the battery is either charging or on a float charge. For an AGM gel cell battery, 12.8 volts is 100% state of charge, so the battery was fully charged.

When the bike is running and above 2000 RPM, you should see 13.8 volts (or thereabout) on the battery terminals. If you are running the bike and seeing only 12.5, that indicates that the alternator is not charging the battery. So it's possible that the old battery was bad because the alternator isn't functioning.

I went after reading your reply and disconnected the terminal from the alternator to the lower dog-bone screw ... cranked the 1500 and wasnt getting anything from the alternator at 2000+ rpm's .... I then put the terminal back on the dog-bone and cranked the 1500 ... it showed 12.55 ... so the battery was back feeding through the dog-bone ... so now it's alternator time in my opinion

The alternator will not produce electricity if it doesn't SENSE electricity. You can spin it all day long, but if the sense/output (most alternators today combine them into one) isn't connected to a battery, it won't produce anything. It has no permanent magnets in it - it requires power from the battery to energize the field coil, which is used to induce power in the windings. No battery power in the field coil, no power generated.

That said, the fact that you're only getting 12.5 volts when connected, says that yes, the alternator is not functioning.

[in2it]

I changed out the alternator ...and low and behold I had a reading at the dogbone of 13.89 ... wish to thank everyone who offered advice on the problem ... I have learned about the Battery and electrical components and how they work together ... the what, how, and why...again thanks