Topic: More charging problems / chicken or egg?

[TwoTired]

Really?  You have 1034 front bulbs in your vetter?

The voltage measurement fro battery POS to Vreg black was meant to be with headlight and key switch on.  With an analog meter you will have to pay attention to meter polarity, which means you'll have to put the black probe on the black vreg terminal and the red probe on the POS terminal.

You know, you can get a digital multimeter for about $10 from Harbor freight.

The other tests you did, indicate a .7V drop between the battery and the Vreg terminal assuming that the battery 11.2V (dead) was still the same potential after you made the other measurements (which is unlikely).

However, your assumption that the Green wires, the frame and Battery negative terminals is unproven.  This path is just as important as the the +12v path for voltage loss integrity.

Anyway, none of the testing shows a cause why the alternator isn't keeping the battery charged.

Are you sure all six diodes in the Rectifier are good?
Are you sure all three connections from stator to rectifier are good?
I'm wondering if there is a phase inop.
Think you can measure AC volts delivered to the rectifier?

Are there any signs that the bike was dropped on the alternator case?

Cheers,

[welnamark]

Twotired:

I believe the Vetter is a Windjammer II.  It utilizes the stock turnsignal stalks, lenses, and bulbs.

The rectifier is a new unit from Oregon Motorcycle Parts.  Before my last ride i checked all diodes for infinite resistance one direction and continuity in the other and it checked out.  I can take actual resistance measurements if it would be helpful.

I will check resistance in the yellow stator wires this evening.  This is done by measuring resistance from where the yellow wires connect to the stator to where the yellow wires end at the rectifier plug....correct?

The bike is really really clean.  I see no evidence that it has ever been dropped.

I can measure AC voltage to the rectifier.  I do this by connecting positive meter lead to ?? wire on rectifier plug (rectifier disconnected?) and grounding the black meter lead?  Do we want voltage readings at a range of engine RPM's here?

Thanks for sticking with me on this one.

Mark

[TwoTired]

The rectifier is a new unit from Oregon Motorcycle Parts.  Before my last ride i checked all diodes for infinite resistance one direction and continuity in the other and it checked out.  I can take actual resistance measurements if it would be helpful.

While it is probably good, it would be nice to have a verification.  Good parts can be made bad, and it is really only brand new until it has had power applied to it.  Then it is a used part.

I will check resistance in the yellow stator wires this evening.  This is done by measuring resistance from where the yellow wires connect to the stator to where the yellow wires end at the rectifier plug....correct?

That checks the interconnect wires. Nice to have that unknown moved into the Known good column.

The bike is really really clean.  I see no evidence that it has ever been dropped.

OK. I'm mainly interested in the stator cover. Look for impact marks or unexplained scratches all over it, side and bottom.

I can measure AC voltage to the rectifier.  I do this by connecting positive meter lead to ?? wire on rectifier plug (rectifier disconnected?) and grounding the black meter lead?  Do we want voltage readings at a range of engine RPM's here?

You will use the AC volts setting on your meter.  I don't know which ranges you have available on your meter.  But, you should expect up to 70V maybe 80V (depends on system load), so select a range that won't overload the meter input.
You will place one probe on the Green rectifier connection and probe each of the Yellow wires at the rectifier in turn.  The frequency will change with RPM.  Most cheap meters are calibrated for 60 Hz in the US.  So, while it may not be totally accurate, it should give us an idea that all phases of the Alternator output are giving us the required power.  Just a heads up, we are never going to want to see less than 30VRMS at each phase output of the stator.

It may seem like a lot to ask.  But, just like taking measurements of the DC at multiple RPMs and system loads, I'd like three AC values under the same conditions; RPM and headlight on or off.
Testing usually involves gathering enough data until the data itself points to the problem area.  Sometimes you can stop gathering data when a smoking gun is found.  But, unless you know what you are looking for, the smoking gun may not look like one to the uninitiated.

I've been away, so forgive a possible repeat question.  Have you already measured the stator resistance and checked each of the stator wires for continuity to the engine case?

Cheers,

[welnamark]

Here is the new data.  I bought a digital meter last night because i was not getting precise resistance data on my analog meter.  I was also not able to finish the alternator AC voltage output testing because at the time it was too late to find a helper to man the throttle for me.  I will finish this procedure Saturday morning.

BATTERY VOLTAGE, NO LOAD:  12.58V

BATTERY VOLTAGE, FULL LOAD:  12.16V

Voltage Regulator testing:
Resistance between I and F poles:  0 ohms
Resistance between white and green wires:  3.9 ohms

Voltage Rectifier test (V Rectifier unplugged):

forward bias yellow to green resistance:
y1:  Infinite
y2:  Infinite
y3:  Infinite

reverse bias yellow to green resistance:
y1:  3.77 ohms
y2:  4.57 ohms
y3:  4.60 ohms

forward bias red/white to yellow resistance:
y1:  Infinite
y2:  Infinite
y3:  Infinite

reverse bias red/white to yellow resistance:
y1:  3.95 ohms
y2:  4.16 ohms
y3:  3.89 ohms

Stator interconnect wires from stator to V Rectifier plug (should be around 0 ohm resistance):
y1: 
y2:  (must be doing this test wrong.  I can get no continuity on this test.)
y3:

Stator interconnect wires insulation check yellow stator wire to chassis / ground (should be infinite ohm resistance):
y1:  Infinite
y2:  Infinite
y3:  Infinite

STATOR check: (resistance should be around .5 ohm)
The resistance between 1 and 2 yellow stator wires =  .65 ohms

The resistance between 1 and 3 yellow stator wires =  .65 ohms

The resistance between 3 and 2 yellow stator wires =  .65 ohms

AC voltage to the rectifier, bike running, rectifier unplugged (should be between 30 and 80 AC Volts):
HEADLIGHT ON:
Green to Y1:
1000rpm  10.5 AC volts
3000rpm
5000rpm

Green to Y2:
1000rpm 9.0 AC volts
3000rpm
5000rpm

Green to Y3:
1000rpm  9.4 AC volts
3000rpm
5000rpm

HEADLIGHT OFF:
Green to Y1:
1000rpm  9.5 AC volts
3000rpm
5000rpm

Green to Y2:
1000rpm  9.3 AC volts
3000rpm
5000rpm

Green to Y3:
1000rpm  9.8 AC volts
3000rpm
5000rpm

[TwoTired]

Voltage Regulator testing:
Resistance between I and F poles:  0 ohms
Resistance between white and green wires:  3.9 ohms

This is kinda low.  The field coil s/b 5 ohms.  Were these wires still connected to the Vreg?  I don't know what is inside your replacement vreg that may change the field coil resistance reading.
FYI: A field coil resistance lower than spec can cause weak alternator output.

Stator interconnect wires from stator to V Rectifier plug (should be around 0 ohm resistance):
y1:
y2:  (must be doing this test wrong.  I can get no continuity on this test.)
y3:

You really need to verify that the stator is electrically connected to the rectifier.  Just one of them open will diminish stator output capability.

AC voltage to the rectifier, bike running, rectifier unplugged (should be between 30 and 80 AC Volts):
HEADLIGHT ON:
Green to Y1:
1000rpm  10.5 AC volts
3000rpm
5000rpm

HEADLIGHT OFF:
Green to Y1:
1000rpm  9.5 AC volts
3000rpm
5000rpm

Here you can see why the alternator doesn't charge the battery at idle.  Even a 100% AC to DC conversion won't be enough to exceed a full battery voltage level.  Batteries only charge when the applied voltage exceeds its no load voltage.

The usual cause is more load on the stator than it can produce.  The load draws energy out of the windings before it can reach peak potential.  In this system, output current is self limiting, it can never produce more power than it's rated capacity for this reason, btw.

Another possible cause is a yellow wire disconnect from the system, allowing only 2/3 of the stator to function.  Each phase output is a path of current for each of the other two phases.  If one phase is open, the peak ACV development on each of the remaining legs is reduced.

I would have expected the "headlight off" AC volts to be higher.  But, the battery increases it's demand for charge power as it gets lower in charge level.

You may wish to test the headlight off sequence first, the save the battery from depletion.

You might also wish to get test leads with alligator clips (or some other attachment device, there are many kinds), to free your hands during the test.

Cheers,

[welnamark]

The field coil test was taken with the Vreg disconnected.  Should I replace the field coil?  My Vreg is still stock.  I only replaced the Vrectifier.

(Quote)
You really need to verify that the stator is electrically connected to the rectifier.  Just one of them open will diminish stator output capability.

I am unsure why I can't get continutiy on this test.  I am trying to measure resistance from the yellow stator wires at their end at the plug to where the three copper looking wires come out of their insulation at the stator.  Are the copper looking wires that make up the windings coated with something?

I will complete the rest of this testing saturday morning.

[TwoTired]

The field coil test was taken with the Vreg disconnected.  Should I replace the field coil?  My Vreg is still stock.  I only replaced the Vrectifier.

The 550 Field coil is supposed to be 4.9Ω +- 10%
If yours is 3.9Ω, it probably has shorted windings and needs replacement.  Such a failure will make the alternator output weak.

I am unsure why I can't get continutiy on this test.  I am trying to measure resistance from the yellow stator wires at their end at the plug to where the three copper looking wires come out of their insulation at the stator.  Are the copper looking wires that make up the windings coated with something?

In order to lay the copper windings against each other, the copper is coated with an insulative coating.  It is not wise to pierce those coatings as they also prevent corrosion.  Any scraping/piercing should be repaired after the test probe process with a dab of epoxy or liquid vinyl.  Why can't you find a soldered connection to probe? 

Anyway, where did you probe for winding resistance of the stator?  Those points prove continuity exists at that point inward to the stator.  You just need to prove those points to the rectifier connections to verify the entire circuit.

Cheers,

[welnamark]

I will retest field coil tonight and if i get a reading similar to 3.9 ohms i will replace.

I have been probing for winding resistance of the stator between yellow 1 and 2, yellow 2 and 3, and yellow 1 and 3 at the plug at the voltage recifier.

[TwoTired]

I have been probing for winding resistance of the stator between yellow 1 and 2, yellow 2 and 3, and yellow 1 and 3 at the plug at the voltage recifier.

If you got those .65Ω readings at that point, then you also verified the interconnect wires, too.

It is as important to know where and how readings were measured as the readings themselves.

Cheers,

[welnamark]

AC voltage to the rectifier, bike running, rectifier unplugged (should be between 30 and 80 AC Volts):HEADLIGHT ON:
Green to Y1:
1000rpm  10.5 AC volts
3000rpm  20.0 AC volts
5000rpm  29.8 AC volts

Green to Y2:
1000rpm  9.0    AC volts
3000rpm  19.25 AC volts
5000rpm  29.4  AC volts

Green to Y3:
1000rpm  9.4    AC volts
3000rpm  20.00 AC volts
5000rpm  31.1   AC volts

HEADLIGHT OFF:
Green to Y1:
1000rpm  9.5   AC volts
3000rpm  21.0 AC volts
5000rpm  32.8 AC volts

Green to Y2:
1000rpm  9.3   AC volts
3000rpm  20.6 AC volts
5000rpm  32.8 AC volts

Green to Y3:
1000rpm  9.8   AC volts
3000rpm  21.4 AC volts
5000rpm  33.0 AC volts

The field coil now tests fine at 4.6 ohms (white to green field coil wires at voltage regulator).

Where do i go from here??  The charging system is functioning, but not up to spec.  I took the bike for a 60 mile trip yesterday with the headlight unplugged and tested the battery when i got home at 12.6 volts.

[TwoTired]

Depending on the test circumstances (load or no load bike running or not running), a 12.6V battery reading is a fully charged battery.

The alternator is certainly putting out enough power to charge the battery at 3000 RPM and above.
Have you measured the voltage on the white and green wires at those RPM settings, headlight on and headlight off?
How about the rectifier output (Red and Green)?

Btw, I told you the alternator might be 30 to 80 volts so you could set your meter range with safety to the meter.  Not all alternators will reach 80 V  (the number is quite load dependent).  But if you are dealing with unknowns, best to set the meter where it won't be damaged.

The ac voltage must be higher than the battery voltage and the diode voltage drop in order to change it.  The diodes drop about .7 v each, so subtract 1.4V from the ac volts measurement.

The lowest 3000 RPM reading you took was 19.25V Even minus 1.4 yields 17.75V   So, all three phases develop enough power to overcharge even a full 14.5 V battery.  No so much at idle, though (as can be expected).

You may wish to examine the wires/connections between the rectifier and the battery posts.

Cheers,

[welnamark]

Alright.  So i will conduct the following tests this evening:

AC VOLTAGE AT VOLTAGE REGULATOR (MEASURED BETWEEN WHITE AND GREEN WIRES)
HEADLIGHT OFF:

1000 RPM:
3000 RPM:
5000 RPM:

HEADLIGHT ON:

1000 RPM:
3000 RPM:
5000 RPM:

VOLTAGE RECTIFIER OUTPUT DC VOLTS (TAKEN BETWEEN RED AND GREEN WIRES)
HEADLIGHT OFF:

1000 RPM:
3000 RPM:
5000 RPM:

HEADLIGHT ON:

1000 RPM:
3000 RPM:
5000 RPM:

RECTIFIER TO BATTERY WIRE CONTINUITY CHECK (RESISTANCE OHMS)

Red / white wire at Rectifier to POS battery terminal lead:

Green wire at Rectifier to NEG battery terminal lead:

So i can continue to understand more about what i'm doing here and the system in general what will be the difference beween the charging system output in ac volts I measured at the voltage rectifier and the output i am going to measure in ac volts at the voltage regulator other than location?  When i measured at the Rectifier i was measuring each yellow wire or "phase" so at the voltage regulator am i measuring the average of the three phases?

[TwoTired]

Alright.  So i will conduct the following tests this evening:

AC VOLTAGE AT VOLTAGE REGULATOR (MEASURED BETWEEN WHITE AND GREEN WIRES)

This had better be a DC voltage test.

So i can continue to understand more about what i'm doing here and the system in general what will be the difference beween the charging system output in ac volts I measured at the voltage rectifier and the output i am going to measure in ac volts at the voltage regulator other than location? 

AC volts should only exist at the stator outputs. Everywhere else on the bike should be DC, even if they are variable in potential.
The regulator outputs can be variable DC levels.  But, this is known as "ripple" or perhaps a varying control voltage.  AC volts refers to "zero crossings", where the voltage swings both positive and negative about a zero volt potential.

When i measured at the Rectifier i was measuring each yellow wire or "phase" so at the voltage regulator am i measuring the average of the three phases?

No. The rectifier output averages the three AC phases while converting to DC.  This power goes to battery and bike loads.
The voltage regulator controls the strength of the magnetic field presented to the stator.  When the battery volts are low, it presents full DC power to the alternator field making the electromagnet as strong as it can be.  When the battery is full, the Vreg reduces the DC voltage sent to the alternator field coil, making the electromagnet weaker.  The stator then creates less output power so as not to overcharge the battery.

The Field coil makes a magnetic field.  The rotor makes the magnetic field alternate in polarity.  The polarity crossings impressed upon the stator windings induce a voltage in those windings.

Cheers,

[welnamark]

I think i got it.  I mistakenly thought the vreg regulated the stator output to the vrectifier, but instead the vreg controls output to the field coil TO control the output of the stator?

When I'm measuring the DC Voltage output of the regulator to the field coil should the green and white wires be disconnected from the field coil?

When I'm measuring the DC output of the rectifier i obviously can't unplug it to access the red/white wire.  Where would be a convenient place to access it?  On my wiring diagram it looks like the red/white wire output at the rectifier goes to the battery.  But I've already measured DC voltages at the battery.

I apologize for my confusion.

[TwoTired]

I think i got it.  I mistakenly thought the vreg regulated the stator output to the vrectifier,

Well, indirectly, yes.

but instead the vreg controls output to the field coil TO control the output of the stator?

Correct

When I'm measuring the DC Voltage output of the regulator to the field coil should the green and white wires be disconnected from the field coil?

Connected is better, as the system will be in a functional mode.  If you disconnect it, the vreg will try to tell the alternator to work at max and should provide all of the voltage present on the black wire sense and supply vreg input onto the white wire.

When I'm measuring the DC output of the rectifier i obviously can't unplug it to access the red/white wire.  Where would be a convenient place to access it?  On my wiring diagram it looks like the red/white wire output at the rectifier goes to the battery.  But I've already measured DC voltages at the battery.

I apologize for my confusion.

It's true that in-circuit testing can be a challenge.  Sometimes, a very pointy probe can pierce the insulation of a wire to gain connection with the wire inside.  It's usually best to patch such an insulation hole with liquid vinyl afterwards.

What we are trying to establish is that all power from the rectifier is getting to the battery posts.

Cheers,

[welnamark]

Before testing Battery Voltage no load:  12.39V

DC VOLTS VOLTAGE RECTIFIER OUTPUT  (MEASURED BETWEEN RED AND GREEN WIRES AT  V RECT. (V RECT. CONNECTED))

HEADLIGHT OFF:
1000 RPM:  12.85 V
3000 RPM:  14.80 V
5000 RPM:  14.58 V

HEADLIGHT ON:
1000 RPM:  11.80 V
3000 RPM:  12.60 V
5000 RPM   14.40 V

RECTIFIER TO BATTERY WIRE CONTINUITY CHECK (RESISTANCE OHMS)

Red / white wire at Rectifier to POS battery terminal lead:  0.0 Ohms
Green wire at Rectifier to NEG battery terminal lead:          0.0 Ohms

Overjoyed that i measured almost 14.5 Volts rectifier output i quit my other testing plans at this point and measured system output at the battery, full load @ 5000 RPM and read 14.1V.

Can we consider this job done?

I think that some of my initial testing after installing the new rectifier may have been flawed.  While testing voltage outputs this time around i noticed that once the engine settled in at the rmp range i was testing for that it took at least 5 seconds for the voltage to climb up to it's peak and level off.  With you hands full of test probes and throttle and the engine screaming in your ear at 5000 rpm 5 seconds can seem like a long time..........

[TwoTired]

I think your charging system tests in good health.

If you continue to have problems, you might consider the battery may be damaged.  They don't like to be deep discharged- ever. Repeated discharge/charge cycles will shorten their life, and they lose vitality.

Cheers,

[welnamark]

Excellent.  Thanks so much for your wisdom and expertise.  I couldn't have done it without you!