Rewound Alternator Rotor gouges, trouble shooting charging system.

[75XSFLORIDA]

Thanks a lot. I will check all of that. Right now across the terminals at 2500 RPMs I’m about 14.7 to 14.8. But it’s not accurate if I have a voltage drop so I will try to remedy that. Because if say im at 14.5V and I have a half a volt voltage drop, that remains im pumping 15 into the battery which is not good.

 

[Paul Sutton]

If you have 14.7V to 14.8V across the battery terminals at 2500 rpm then that is what your electrical system is operating at. Is it really 15V, no because the voltage across the battery terminals shows the system is at 14.7V to 14.8V. We have uncertainty because we believe there are voltage drops. Minimizing the voltage drops will remove that uncertainty and give you more confidence in what the battery shows.

Things are looking good...

 

[75XSFLORIDA]

If you have 14.7V to 14.8V across the battery terminals at 2500 rpm then that is what your electrical system is operating at. Is it really 15V, no because the voltage across the battery terminals shows the system is at 14.7V to 14.8V. We have uncertainty because we believe there are voltage drops. Minimizing the voltage drops will remove that uncertainty and give you more confidence in what the battery shows.

Things are looking good...

So if the drop at the brown wire is .59 that means im overcharging the system by that much right which is why to compensate youd turn down the regulator correct? But if im 4.7 across the terminals does that mean thats AFTER the brown wire so thats accurate and you dont have to take the drop into consideration?

 

[Paul Sutton]

Just had a hot drink so ready to go.

If you have a voltage drop of 0.6V in the wiring system this mean there is effectively a small valued resistor in the circuit due to corrosion or a loose connector.

At the moment the voltage reading across the battery terminals at 2500 rpm tells you the system is running at 14.7 - 14.8 volts. This system voltage is the result of the regulator and the regulating effect of the small resistance.

We can say that the regulator is physically set for 15.3 - 15.4 volts and this is how we are offsetting the effect of an unwanted 0.6 voltage drop. As long as nothing changes in your electrical system (e.g. the 0.6V drop remains permanently) then your regulator is set correctly to give a working system voltage of 14.7 - 14.8 volts. We know this because the voltmeter said so.

However, if for some reason you were out riding and the electrcal connectors got bounced about such that the small resistance disappeared completely then the system voltage may possibly jump up to 15.3 - 15.4 volts as measured across the battery terminals because the regulator is physically adjusted for this voltage level. I believe this is your concern in a round about way.

If you can guarantee the 0.6V drop will always be present in your Brown wiring path then there is nothing to worry about. If you cannot guarantee this then there is uncertainty that one day your charging voltage my jump up and out of specification and possibly cause you problems. Therefore, if you can minimze the voltage drop close to zero then in all probability the worst thing to happen is someday a connector develops a slight resistance so a voltage drop rises and the voltage on your system may drop slightly - no big deal.

On my old XS650SH I was able to get my voltage sensor wire to the regulator to within 0.1 - 0.2 volts of the battery reading. I suggest you check the ignition switch first then try to determine where the voltage drop occurs in the brown wire. If the switch is not the problem then you can try bypassing the existing brown wire to positively determine what is at fault.

Let us know what switch cleaning yields.


Note: On old wiring it is not unusual to see a voltage drop due to oxidation where the copper wire enters a crip connector or where the copper wire enters a solder joint in a switch.

Warning: Doing this sort of fault finding can lead to the ignition being on for extended periods. This can damage the ignition coils. Perhaps disconnect the brown wire to the coils unless you need the engine running.

 

[75XSFLORIDA]

Just had a hot drink so ready to go.

If you have a voltage drop of 0.6V in the wiring system this mean there is effectively a small valued resistor in the circuit due to corrosion or a loose connector.

At the moment the voltage reading across the battery terminals at 2500 rpm tells you the system is running at 14.7 - 14.8 volts. This system voltage is the result of the regulator and the regulating effect of the small resistance.

We can say that the regulator is physically set for 15.3 - 15.4 volts and this is how we are offsetting the effect of an unwanted 0.6 voltage drop. As long as nothing changes in your electrical system (e.g. the 0.6V drop remains permanently) then your regulator is set correctly to give a working system voltage of 14.7 - 14.8 volts. We know this because the voltmeter said so.

However, if for some reason you were out riding and the electrcal connectors got bounced about such that the small resistance disappeared completely then the system voltage may possibly jump up to 15.3 - 15.4 volts as measured across the battery terminals because the regulator is physically adjusted for this voltage level. I believe this is your concern in a round about way.

If you can guarantee the 0.6V drop will always be present in your Brown wiring path then there is nothing to worry about. If you cannot guarantee this then there is uncertainty that one day your charging voltage my jump up and out of specification and possibly cause you problems. Therefore, if you can minimze the voltage drop close to zero then in all probability the worst thing to happen is someday a connector develops a slight resistance so a voltage drop rises and the voltage on your system may drop slightly - no big deal.

On my old XS650SH I was able to get my voltage sensor wire to the regulator to within 0.1 - 0.2 volts of the battery reading. I suggest you check the ignition switch first then try to determine where the voltage drop occurs in the brown wire. If the switch is not the problem then you can try bypassing the existing brown wire to positively determine what is at fault.

Let us know what switch cleaning yields.


Note: On old wiring it is not unusual to see a voltage drop due to oxidation where the copper wire enters a crip connector or where the copper wire enters a solder joint in a switch.

Warning: Doing this sort of fault finding can lead to the ignition being on for extended periods. This can damage the ignition coils. Perhaps disconnect the brown wire to the coils unless you need the engine running.

So, when riding the bike or revving the engine, the voltmeter I have installed on my handlebars, this is the actual voltage that is running thru the system correct? Setting the voltmeter lower compensates for this drop. I think I’m starting to understand.

 

[5twins]

That would depend on where you connected the voltmeter. If it's connected to one of the brown wires coming out of the key switch then yes, it is showing the system voltage. If you connected it directly to the battery then it is showing actual battery voltage, or the amount of voltage being fed to it.

 

[75XSFLORIDA]

That would depend on where you connected the voltmeter. If it's connected to one of the brown wires coming out of the key switch then yes, it is showing the system voltage. If you connected it directly to the battery then it is showing actual battery voltage, or the amount of voltage being fed to it.

Oh I see. It’s actually hardwired to the battery with an SAE.

 

[5twins]

OK then, you can pretty much base your regulator setting on what the voltmeter is showing you. The amount of voltage being fed into the battery is what you want to know and the way you've connected the voltmeter, it should be telling you that.

 

[75XSFLORIDA]

That would depend on where you connected the voltmeter. If it's connected to one of the brown wires coming out of the key switch then yes, it is showing the system voltage. If you connected it directly to the battery then it is showing actual battery voltage, or the amount of voltage being fed to it.

It’s too

OK then, you can pretty much base your regulator setting on what the voltmeter is showing you. The amount of voltage being fed into the battery is what you want to know and the way you've connected the voltmeter, it should be telling you that.

Perfect. And that’s because it’s at the battery as opposed to the headlight switch. I get it. So I guess the good thing is the drop is pretty much irrelevant as long as my voltmeter stays wired the same way, and the volts are within spec, or about 14.6 14.7. … because I have accounted for this drop by setting the regulator correctly.

 

[5twins]

Well, not quite as correctly as most of us like to see. As mentioned, we like to see the low 14's, ideally like 14.2 or 14.3. Get below 14 and the battery may never be brought to a full charge.

Several years back, when I first started getting into the electrical more, and finally checked the charging output on my '78, I found it a bit low, only in the high 13's. Now, I never had battery issues, never had a dead battery, from running it like this but apparently I wasn't giving the battery quite as much charging voltage as it would have liked. The simple regulator adjustment cured it, and then an upgrade to the VR115 auto regulator really fixed it .....

 

[75XSFLORIDA]

Well, not quite as correctly as most of us like to see. As mentioned, we like to see the low 14's, ideally like 14.2 or 14.3. Get below 14 and the battery may never be brought to a full charge.

Several years back, when I first started getting into the electrical more, and finally checked the charging output on my '78, I found it a bit low, only in the high 13's. Now, I never had battery issues, never had a dead battery, from running it like this but apparently I wasn't giving the battery quite as much charging voltage as it would have liked. The simple regulator adjustment cured it, and then an upgrade to the VR115 auto regulator really fixed it .....

View attachment 239244

But where I’m at now, as long as I see mid 14s across my voltmeter that’s connected to the battery and nothing more, then i can leave the regulator adjustment alone correct??

 

[jetmechmarty]

So I just lightly sanded and brought to a shine the male bullet connectors and the headlight harness of the brown and red wire. It looks like my resistance has dropped from 0.29 to 0.23 because of this. But I’m wondering, does the battery voltage have anything to do with this? Meaning The more volts the battery has or the more charged it is or the less charged it is does it affect the voltage drop at the ignition switch or no matter what the volts are across the terminals on the battery, it has no bearing on the drop at the switch, meaning the drop at the switch should be the same regardless, how charged or decharged the battery is? Because now again, I’m seeing 0.23 which is an improvement but I don’t want to say it’s improved because I just took the battery off the tender. I lwant my improvements to have came from me sanding the bullets lol.

E = I * R

Look up Ohm’s Law. It should answer all of those questions easily.

 

[75XSFLORIDA]

Well, not quite as correctly as most of us like to see. As mentioned, we like to see the low 14's, ideally like 14.2 or 14.3. Get below 14 and the battery may never be brought to a full charge.

Several years back, when I first started getting into the electrical more, and finally checked the charging output on my '78, I found it a bit low, only in the high 13's. Now, I never had battery issues, never had a dead battery, from running it like this but apparently I wasn't giving the battery quite as much charging voltage as it would have liked. The simple regulator adjustment cured it, and then an upgrade to the VR115 auto regulator really fixed it .....

View attachment 239244

Here’s what shining up a few bullet connectors does!
12.5v at the ignition switch with key off….0.15v drop with key on. Thats a huge improvement over the 0.29v drop i got yesterday!!

 

[75XSFLORIDA]

Just had a hot drink so ready to go.

If you have a voltage drop of 0.6V in the wiring system this mean there is effectively a small valued resistor in the circuit due to corrosion or a loose connector.

At the moment the voltage reading across the battery terminals at 2500 rpm tells you the system is running at 14.7 - 14.8 volts. This system voltage is the result of the regulator and the regulating effect of the small resistance.

We can say that the regulator is physically set for 15.3 - 15.4 volts and this is how we are offsetting the effect of an unwanted 0.6 voltage drop. As long as nothing changes in your electrical system (e.g. the 0.6V drop remains permanently) then your regulator is set correctly to give a working system voltage of 14.7 - 14.8 volts. We know this because the voltmeter said so.

However, if for some reason you were out riding and the electrcal connectors got bounced about such that the small resistance disappeared completely then the system voltage may possibly jump up to 15.3 - 15.4 volts as measured across the battery terminals because the regulator is physically adjusted for this voltage level. I believe this is your concern in a round about way.

If you can guarantee the 0.6V drop will always be present in your Brown wiring path then there is nothing to worry about. If you cannot guarantee this then there is uncertainty that one day your charging voltage my jump up and out of specification and possibly cause you problems. Therefore, if you can minimze the voltage drop close to zero then in all probability the worst thing to happen is someday a connector develops a slight resistance so a voltage drop rises and the voltage on your system may drop slightly - no big deal.

On my old XS650SH I was able to get my voltage sensor wire to the regulator to within 0.1 - 0.2 volts of the battery reading. I suggest you check the ignition switch first then try to determine where the voltage drop occurs in the brown wire. If the switch is not the problem then you can try bypassing the existing brown wire to positively determine what is at fault.

Let us know what switch cleaning yields.


Note: On old wiring it is not unusual to see a voltage drop due to oxidation where the copper wire enters a crip connector or where the copper wire enters a solder joint in a switch.

Warning: Doing this sort of fault finding can lead to the ignition being on for extended periods. This can damage the ignition coils. Perhaps disconnect the brown wire to the coils unless you need the engine running.

Here’s what shining up a few bullet connectors does!
12.5v at the ignition switch with key off….0.16v drop with key on. Thats a huge improvement over the 0.29v drop i got yesterday!!

 

[650Skull]

Now imaging what a difference cleaning the switch will do.

 

[75XSFLORIDA]

But it’s strange because at the brown wire I’m still getting 11.67 which is what I got yesterday. Shouldnt that be lower since now ignition switch is lower? Doesn’t make sense to me.

Actually we are good!
12.32 battery 11.86 at brown wire, less than .5 volt drop now. Progress. But I think I did the test wrong. I had the ignition on when I measured across the battery terminals. It should be off at that point, correct? And only on when I’m testing the brown wire, correct?

 

[75XSFLORIDA]

Test at the regulator again this time move the black probe to the black wire going to regulator.
Keep red probe on the brown wire.
View attachment 239181

I thought I made progress today but I think I’m doing the test wrong. When I test out the brown wire the ignition switch should be on correct but then when I test across the battery terminals ignition switch should be off. Is that right?

 

[75XSFLORIDA]

This is where i am now.
This is with old mechanical regulator

Jp,

I forgot, when i test brown wire at regulator the ignition should be on corrrect?? Across the battery terminals, ignition on OR off? Today I think I did the test wrong because I had the ignition on when I measured across the terminals, so of course the reading between the two tests will be closer between the two tests, and not accurate… I was happy momentarily because I thought I got voltage drop improvement from yesterday but maybe not the case

 

[GLJ]

I thought I made progress today but I think I’m doing the test wrong. When I test out the brown wire the ignition switch should be on correct but then when I test across the battery terminals ignition switch should be off. Is that right?

I would do both tests with the ignition switch on. Reason being with the ignition switch off the battery voltage will be higher than when on.

 

[75XSFLORIDA]

I would do both tests with the ignition switch on. Reason being with the ignition switch off the battery voltage will be higher than when on.

Thats correct and thats what i was thinkin as well…this is great news then. Look at these readings with ignition ON in both tests. I had a feeling it supposed to be on in both, but I forget from yesterday…went from a .59 to a .26 drop from yesterday compared to just now just by cleaning a few male bullets. That’s basically only a quarter volt drop which I’m happy with. Pics are from right now