Alternator with higher output?

[68C]

Have a look at this site, has a basic tutorial on motorcycle charging systems, they also sell rectifier regulators.

 

http://www.electrosport.com/technical-resources/technical-articles/how-motorcycle-charging-system-works

[Kiwi_Roy]

Have a look at this site, has a basic tutorial on motorcycle charging systems, they also sell rectifier regulators.

 

http://www.electrosport.com/technical-resources/technical-articles/how-motorcycle-charging-system-works

That's quite a good article but doesn't really apply to a Guzzi. Our permanent magnet alternators are single phase and don't get shorted out like that. The regulator looks at it's voltage reference (the black wire to case)

if it's less than 13.8 it turns the SCRs ON,

if it's above 13.8 it turns the SCRs OFF

Here's a diagram I drew of it, note the waveform on the RH side, this is what I observed with my scope.

Regulator Schematic - With Notes.pdf

 

 

It's interesting the article gives 14.4 Volts for the regulator setpoint.

The Ducati Energias I have tested have a setpoint of 13.8 Volts but it doesn't include the additional voltage drop in the standard wiring.

Tom now has a setpoint of 13.8 + 0.6 (diode) = 14.4 Volts

 

 

Roy

[68C]

Another one of your excellent diagrams Kiwi_Roy.

 

Now I can see that any resistance in the lines from the rectifier/regulator to the battery will cause a voltage drop that is not seen by the regulation circuit. The previous posts effectively reduce the voltage reaching D1 so the output voltage increases until the voltage at D1 is satisfactory, although the actual output is above nominal voltage. I assume the battery absorbs this excess voltage and prevents damage to other components. Is that how you see it.

[Kiwi_Roy]

Another one of your excellent diagrams Kiwi_Roy.

 

Now I can see that any resistance in the lines from the rectifier/regulator to the battery will cause a voltage drop that is not seen by the regulation circuit. The previous posts effectively reduce the voltage reaching D1 so the output voltage increases until the voltage at D1 is satisfactory, although the actual output is above nominal voltage. I assume the battery absorbs this excess voltage and prevents damage to other components. Is that how you see it.

You've got the idea

The current pulses are as high as 30 Amps but then there are times when the current is zero like I show on the RH of drawing the battery absorbs the high current pulses and presents nice smooth voltage to the bike if you were to measure the average current to and from the battery they would be similar. In this it's similar to all the other permanent magnet alternators some short out excess ours interupts excess.

The wound rotor type as most cars and earlier Guzzis have is different, there they make the magnets stronger or weaker to regulate the current, they don't need to short or interupt the flow.

 

The battery doesn't realy see excess Voltage 14.4 is fine as per the article you posted, Luigi set the regulator low (13.8) to allow for the voltage drop.

 

However if you have any abnormally high resistance in the reference circuit for example a loose headlight relay base the regulator will never turn off, something has to give hopefully the 30 amp fuse will blow. I suspect this is the cause of melted diodes in the ones I have dissasembled.

 

Any time you see the dash lights flickering or perhaps the tach going crazy check it out, they share the same source as the reference.

[docc]

And, perhaps, contributes to the commonly melted 30 amp mini fuse? This was always assumed to simply be the inadequate contact area in the fuse block. Although, I melted a couple mini- fuses in external holders (or charred their contacts off).

 

My Maxi-fuse has stayed well with no melt.

[Kiwi_Roy]

I had some time today so I did some testing on my V11 Sport

The wiring on this bike is in good condition. I can easily disconnect the added headlight relays and it reverts back to the original headlight wiring.

 

To test the theory that there is voltage drop between the battery and the regulator reference wire I connected my multimeter from battery Positive to

the connector where the regulator Black wire plugs in.

 

Here is the circuit for the relays showing the different wiring

Charging Circuit Reference.pdf

As I note, not all bikes have the same reference wiring, I think mine is unusual in that the headlight also goes directly through the N/C Start Relay contact, others use this contact to power the headlight relay coil. Coil wiring for the after market headlight relay/s will be different than shown, I just want to show the main current wiring.

 

Test 1 with headlight powered through original wiring

At first when I turned it on I saw up to 1 Volt drop, it seemed to drift around a bit. I figured there must be a bad contact somewhere.

After wiggling the relays and fuses around the voltage drop is 650 mV or 720 mV depending on which headlight beam is selected. This mV is added to

the 13.8 regulator setpoint so the battery will charge to 14.45 or 14.52 Volts depending on headlight.

 

Test 2 with headlight powered through added headlight relays

Heres the crunch, when I power the headlight through the relays, because now most of the current is bypassed the voltage drop lowers to around 50 mV,

so now the battery will only charge to 13.85 Volts 0.6 Volts lower.

 

This is the problem that prompted Tom into asking about a higher output alternator.

 

In Conclusion

Headlight relays might improve your lighting but your charging has suffered, you need to correct for the feedback you have lost.

If you add driving lights they should be powered from a different circuit or they will add to the Voltage drop and likely cause overcharging.

Any additional resistance i.e. dirty relay base may cause the regulator to think the battery is flat resulting in overcharging and possible regulator failure.

 

Hope this has given you something to think about

 

I would be very interested to learn what Voltage drop other riders measure from Battery + to the reference at the regulator (female connector where the Black wire plugs in)

Do this test with the motor OFF but lights ON

I would also like to know if you have after market headlight relays.

Which model and year your bike is?

If your after market headlight relays are wired differently perhaps you could send a sketch.

 

Thanks

 

Roy

[Tom M]

Great stuff Roy! I have the Eastern Beaver headlight relay harness installed so I might be a low charge rate victim. My bike is somewhat disassembled in my basement right now but when I get it back together I'll try and take some voltage measurements.

[68C]

What if we relocate the sense wire to the output from the ignition switch, this would be nearer to the battery and give a more accurate sense of battery voltage. Headlight voltage would no longer be sensed so we can add relays without any problem. I believe we cannot connect it direct to the battery as the regulator would then always be live and so flatten the battery.

[Kiwi_Roy]

What if we relocate the sense wire to the output from the ignition switch, this would be nearer to the battery and give a more accurate sense of battery voltage. Headlight voltage would no longer be sensed so we can add relays without any problem. I believe we cannot connect it direct to the battery as the regulator would then always be live and so flatten the battery.

With headlight relays added the regulator sense wire is very close to actual battery voltage so it will charge to 13.8 Volts, same as if you wired it to the ignition switch. Tom added a diode in series with his reference wire this makes the regulator think the battery is less by 0.6 Volts so it cranks the battery Voltage up to 14.4 as it would be with original wiring.

I'm not a fan for running anything important directly through the ignition switch, as the bike ages the switch builds up resistance which might cause the regulator to go full on and cook something. Note, all bikes use relays to power the ECU coils injectors etc.

 

As I said previously, before adding anything ground the regulator properly, bad grounding also causes low charging.

[68C]

Initialy a bit confused by your answer, my fault not yours! So the volt regulator isnt set to a normal 14.4 volts for good battery charging but to a lower 13.8 volts! Then the permanently on headlamp drops the voltage below 13.8 volts at which point the regulator ups the voltage until the dropped voltage is back to 13.8, this needs 14.4 volts on the output to the battery to achieve. The diode effectively recalibrates the OEM regulator. I can feel a John McEnroe moment coming on, I though dear old Joe Lucas (the prince of darkness) had some odd ideas but this Guzzi one beats me. The engineering answer I suppose is to make up a new loom with decent wires and a more convential use of relays, the ignition and light switches only handling the field current to these relays. Might be a good time to add an alarm/immobiliser, power sockets etc.

 

Oh, of course also fit a normal 14.4 volt rectifier/regulator.

[docc]

But what does it mean:

 

This 2000 Sport has OMRON 0264A22A relays (one for the hi-beam, one for the low) in the headlamp shell wired directly from the battery through a 10 amp circuit breaker, each grounded to the frame and their coils activated by the stock wiring..

 

The voltage drop from the reference is 140mV on low beam, 160mV hi beam.

 

I see why the electric jacket does not change the reference voltage at all since the reference circuit is the headlamp /brake lamp circuit only.

 

I am certainly unclear why a diode is the answer and not a resistor to increase voltage drop, but I am admittedly clueless on the electronics.

[Kiwi_Roy]

But what does it mean:

 

This 2000 Sport has OMRON 0264A22A relays (one for the hi-beam, one for the low) in the headlamp shell wired directly from the battery through a 10 amp circuit breaker, each grounded to the frame and their coils activated by the stock wiring..

 

The voltage drop from the reference is 140mV on low beam, 160mV hi beam.

 

I see why the electric jacket does not change the reference voltage at all since the reference circuit is the headlamp /brake lamp circuit only.

 

I am certainly unclear why a diode is the answer and not a resistor to increase voltage drop, but I am admittedly clueless on the electronics.

Your wiring is pretty much the same as mine, I see about 50 mV with the relays 600 - 700 without.

I predict your battery is only charging up to 13.95V or thereabouts but I may be wrong.

It would be interesting to know what the peak battery voltage you see and what it settles out at say half hour after riding.

No reason for a diode really except it has a fixed voltage drop of 600mV (no calculation required). Yes a resistor will work also to change the setpoint but the trick is to figure out the value because inside the regulator it splits in two, I'm not sure if the split is constant or changes with revs. You could try a wirewound rheostat of 50 Ohms

Do you think your charging is adequate? If so don't worry about it

[docc]

I just rode 25 miles three hours ago. Voltage is 13.02. At idle: 12.60 and everything over 2500 rpm: 14.24.

 

Seems ok to me, but it's always a worrisome subject and we all want to be getting the most out of the charging system.

 

If I added the diode, wouldn't it boost the charge to 14.84? That seems a bit high . . .

[Kiwi_Roy]

I just rode 25 miles three hours ago. Voltage is 13.02. At idle: 12.60 and everything over 2500 rpm: 14.24.

 

Seems ok to me, but it's always a worrisome subject and we all want to be getting the most out of the charging system.

 

If I added the diode, wouldn't it boost the charge to 14.84? That seems a bit high . . .

Yours seems fine, there must be something in your wiring or regulator that's different, i wouldn't worry about it.

Perhaps you could scan your wiring diagram and also indicate how your after market relays are connected.

 

Thanks

 

Roy

[docc]

Link here to the wiring in the headlamp bucket.

 

And here for the power distribution from the battery.

 

Also, the battery and regulator are a year and a half old and the stator is two and a half. I've added all the recommended grounds and regularly serviced connectors. OMRON relays in the relay block as well as the headlamps (x2), and the 30 amp Maxi fuse for the charging circuit.