Battery not charging problem

John OoSTerhuis · Jul 5, 2017

Good advice above, Bob. If the stator is toast there's no need buy a VRR.

Is there an experienced STrider close to Bob that could help him?

I have a longtime ST1100 owner friend that's a great wrench and lives close by (Butler) you. He's no longer on this board, but might be persuaded to help. Lemme know...

Regards, John

Bush · Jul 5, 2017

John OoSTerhuis said:
Good advice above, Bob. If the stator is toast there's no need buy a VRR.

Is there an experienced STrider close to Bob that could help him?

I have a longtime ST1100 owner friend that's a great wrench and lives close by (Butler) you. He's no longer on this board, but might be persuaded to help. Lemme know...

Regards, John

Now there's an offer I wouldn't refuse Bob! Always glad to see John chime in on some of these more technical problems. If he says his friend is a great wrench, all I can say is . . . it takes one to know one.

robertp039 · Jul 6, 2017

First off.... You guys are great and I really welcome all the help you given me! John, That would be great! I will try to see if the alternator is good or bad myself using Bush's instructions. I will let you know. If it is good then I think I can handle installing a new VRR. Again, thanks everyone for your help! I will post results.

John OoSTerhuis · Jul 6, 2017

Email me your particulars, Robert, and I'll try to get you two connected.

John

robertp039 · Jul 6, 2017

Did the test and I was getting around 34 volts on all 3.

dwalby · Jul 6, 2017

Bush said:
Put one voltmeter lead onto one terminal in the ALTERNATOR side of that 3P connector and the other lead on any of the other two, Check the reading, Move the leads to each terminal, such that you have measured all three against each other. All readings should be very similar.

You could also measure each terminal individually with the other lead on the battery ground. That will give you the exact voltage of each phase. If one phase is weak or dead, you'll know exactly how weak it is.

If you measure between any two terminals, you're measuring the voltage difference between the two phases, not an absolute voltage. That's also good, but there's one caveat. If one phase is totally dead, you'll see a voltage that is the difference between zero and the other phase, which will then be much different (higher) than the reading between any two live phases. This is why Bush advised that all the voltages you measure should be very similar.

One more check, with the bike turned off, measure the resistance between each phase and ground, if any of the phases is shorted out then that would confirm any low voltage measurement on that phase.

moddy · Jul 6, 2017

Hi Bob, I just went through this last November. I have a '91 myself. My alternator failure was in the stator winding, part of the alternator the 3 wires come out from, compared to the only other two that remain, the black and white one. You already have a great deal of help here and the only thing I might be able to point out, not being mechanically inclined, if you want to learn, is being able to find someone to help you.
As for the potential on this thread and this forum, it's high. There are scads of pictures, parts lists, specialty tools, and help I've had for 5 1/2 years. We'll be here.

dwalby · Jul 6, 2017

robertp039 said:
Did the test and I was getting around 34 volts on all 3.

hey that's good news, VRR replacement is far easier than the alternator. Just to double check you could check the voltage from each phase to ground and see how consistent they are. That's going to be a lot higher voltage, maybe in the 70-100v range but I've never measured it on an ST alternator so I'm not sure.

robertp039 · Jul 6, 2017

dwalby said:
You could also measure each terminal individually with the other lead on the battery ground. That will give you the exact voltage of each phase. If one phase is weak or dead, you'll know exactly how weak it is.

If you measure between any two terminals, you're measuring the voltage difference between the two phases, not an absolute voltage. That's also good, but there's one caveat. If one phase is totally dead, you'll see a voltage that is the difference between zero and the other phase, which will then be much different (higher) than the reading between any two live phases. This is why Bush advised that all the voltages you measure should be very similar.

One more check, with the bike turned off, measure the resistance between each phase and ground, if any of the phases is shorted out then that would confirm any low voltage measurement on that phase.

I'm getting 79 volts on two pins and only 40 on one of them. The other test on the vrr side had no resistance. On the alternaor side dead shorts on all 3 pins.

dwalby · Jul 6, 2017

robertp039 said:
I'm getting 79 volts on two pins and only 40 on one of them. The other test on the vrr side had no resistance. On the alternaor side dead shorts on all 3 pins.

are you sure they're dead shorts, as in only a few tenths of an ohm for the meter leads? The resistance should be only a few ohms, don't have the manual in front of me so can't give you a precise range, but it shouldn't be zero. Do you have the meter on the lowest resistance range (or auto range?). I'd think if they were dead shorts you wouldn't be seeing any voltage, but no prior experience with this beast so I don't want to make any claims I can't back up with my own experience.

Bush · Jul 6, 2017

Seems to be some conflicting numbers here. On the one hand you got good results from the first dynamic test, then a poor result on one coil using dwalby's test. Then you are claiming all three coils (phases) are shorted to ground, which would mean zero output. On that test for the alternator coils, using your Ohmmeter , you should put one lead on each of the three yellow wires, on the alternator side and the other lead to ground, the negative battery terminal. There should be no continuity to ground on any of the three yellow wires.

Might be time to see if John's friend can help diagnose this.

dwalby · Jul 6, 2017

Hey Bush, I've got a question about the phase-to-phase voltage measurement. In the one time I've had to measure alternator phases, 30 years ago, I used the each phase to ground method, so I've never tried the phase-to-phase method.

Mathematically, it seems to me that the voltage difference between two signals that are 120 degrees out of phase should be much higher than the voltage difference of two signals that are 60 degrees out of phase. Not sure how the multimeter sees this, and it is probably a bit different if you have a cheaper multimeter that does AC averaging vs. a more expensive one that does RMS AC. But given that, it would seem to me that if you measure from one phase to each of the other two, you should not expect to see the same voltage in both cases.

What is your practical experience with this on a properly working alternator, does the meter read the same in both cases?

John OoSTerhuis · Jul 6, 2017

Bush said:
Seems to be some conflicting numbers here.

I agree. The dynamic (engine running) AC check is good, but on the static (engine off) continuity check -

.... put one lead on each of the three yellow wires, on the alternator side and the other lead to ground, the negative battery terminal. There should be no continuity to ground on any of the three yellow wires....

You report all three windings as shorted to ground (complete stator failure).

Someday I'm going to have to have a 28amp owner come to the east coast of Iowa and we'll document the charging tests. Should do a video of the 40 amp alt upgrade too!

John

DeanR · Jul 6, 2017

John OoSTerhuis said:
Someday I'm going to have to have a 28amp owner come to the east coast of Iowa and we'll document the charging tests. Should do a video of the 40 amp alt upgrade too!

John

hmmm?

dwalby · Jul 6, 2017

I think the measurement showing one phase significantly lower than the other two would be consistent with the tester reporting a diode failure. It sensed the voltage droop during the low voltage phase. Why he is seeing dead short to ground is a mystery, but I suspect he's running on 2.5 phases based on the voltage measurements.

He's never measured/reported the charging voltage at the battery with the bike running, that would be good to know too.

Bush · Jul 6, 2017

dwalby said:
Hey Bush, I've got a question about the phase-to-phase voltage measurement. In the one time I've had to measure alternator phases, 30 years ago, I used the each phase to ground method, so I've never tried the phase-to-phase method.

Mathematically, it seems to me that the voltage difference between two signals that are 120 degrees out of phase should be much higher than the voltage difference of two signals that are 60 degrees out of phase. Not sure how the multimeter sees this, and it is probably a bit different if you have a cheaper multimeter that does AC averaging vs. a more expensive one that does RMS AC. But given that, it would seem to me that if you measure from one phase to each of the other two, you should not expect to see the same voltage in both cases.

What is your practical experience with this on a properly working alternator, does the meter read the same in both cases?

I admit that I am not THAT technically knowledgeable about your method of testing the alternator, having only performed dynamic testing between the yellow wires. My digital multimeter is pretty basic - got it on sale at Canadian Tire for $!0.00! - but it does test diodes too.

Your explanation of using the phase to ground method seems logical though and may be more definitive in diagnosing the alternator.

robertp039 · Jul 6, 2017

robertp039 said:
Did the test and I was getting around 34 volts on all 3.

Since this test was positive I ordered a VRR before I read the last posts. I'm hoping that this will be the answer to my charging issue. But it may not be???

If not, John I may need to look up the guy in Butler to help me figure this out.

I'm really hope that the new VRR gets my batter charging again because it is not getting any charge what so ever when I start the engine. My battery reads about 11.7 volts running. I guess the headlight ect.. bring it below 12.7 volts.

Bush · Jul 6, 2017

dwalby said:
I think the measurement showing one phase significantly lower than the other two would be consistent with the tester reporting a diode failure. It sensed the voltage droop during the low voltage phase. Why he is seeing dead short to ground is a mystery, but I suspect he's running on 2.5 phases based on the voltage measurements.

He's never measured/reported the charging voltage at the battery with the bike running, that would be good to know too.

Yes, I agree that we may just be seeing a diode failure from the battery tester's report. I also wonder if Bob performed the continuity tests on the alternator coils properly, since we hadn't given any info on how to do that earlier.

Bush · Jul 6, 2017

robertp039 said:
Since this test was positive I ordered a VRR before I read the last posts. I'm hoping that this will be the answer to my charging issue. But it may not be???

If not, John I may need to look up the guy in Butler to help me figure this out.

I'm really hope that the new VRR gets my batter charging again because it is not getting any charge what so ever when I start the engine. My battery reads about 11.7 volts running. I guess the headlight ect.. bring it below 12.7 volts.

The 28 amp system does not put out its full charge capacity at idle. Do you see any higher charging voltage at the battery if you rev the engine to about 4,000 rpm?

Can you confirm that you have now checked those 3 alternator coils for non continuity in the proper method, as I described earlier? Results?

robertp039 · Jul 6, 2017

I will test again tomorrow. Perhaps I did it wrong. I still hope that I did not waste money buying the VRR.

Battery not charging problem

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