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Battery light flicker

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But that can't be right, can it? The Q3 requires positive GS of 2-4V to conduct, this will never be the case with the Z2 as shown. Also the SCRs seem to be wrong way round and unprotected. The Q2 seems to be more or less permanently on, driven by the alternator's negative half-period...


Has anyone tried simulating this circuit in e.g. SPICE?

LOL, I probably show the Zenner upside down as usual (Zi will be backwards also) I figure the diode should conduct forward in the direction of the arrow at zenner Voltage but of course its the other way.


I believe I have the SCRs shown correctly, visualize one half cycle when the Left yellow is Positive, current goes thru left diode to battery, comes back thru ground thru right hand SCR to the right hand yellow which is Negative.


There may be errors in my interpretation but I think I have shown it correct.

Anyway the charge light circuit is independent of the charging, I have seen it where components were smoked but it still regulated the battery just fine.


I had a hard drive crash and lost my drawing files otherwise I could correct it.

Feel free to pull a regulator apart and make your own drawing, I was lucky with the first one the epoxy was soft, usually the components are destroyed in the process.

All the ones I dissected had one diode lead melted off, they can be soldered back on or supplemented on the outside.

I rode home slowly once with a bridge rectifier in place of the regulator.


BTW I think at a low idle the battery is in a state of Negative charge so flicker is normal, my EV was the same.

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You mean your's actually works? I think mine is activated by phases of the moon.

Docc said "So it can be said that when the battery is fully charged the charging Voltage is the same but the regulator is allowing less current through" Not exactly, it wont let anything through unti

I would put an amount of electrical grease in the cavities before plugging it up for a perfect connection .

Hi Corytrevor


Any chance of a photo showing how you mounted the Voltage Monitor?

Did you connect to battery or through ignition switch?

Seems like something every V11 owner should have.

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I don't have a photo, sorry.


It's mounted in the plastic panel below the windshield, centered and right under the windshield. I got the 8mm version, and drilled a hole with a unibit and installed the led without the bezel, with a dab of Goop to hold it.


I connected the hot side to the circuit with the pilot lamp, gauge lamps, taillight and license light. I have a led taillight bulb, no pilot or license bulb. The voltage drop to the battery is .2v on the hot side. I grounded it to the fairing bracket, 0 voltage drop to the battery. 


I considered a dedicated relay off the battery but it tells me what I want to know even with the small voltage drop. I'm using it to let me know if the charging system fails, not really as a voltmeter but more as a warning light.

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  • 3 months later...


The lamp is controlled by the regulator, not ECU. So no, ECU ground is not the culprit. 


Flicker will be back! ;-)

Haha, yes. Some things do not stay "fixed."


Of course, Guzzi2Go is entirely correct. The new jeweled lenses over the warning lamps make the flicker much more noticeable.


I will need to turn my attention to the Sport's charging system. As luhbo has pointed out (also entirely correctly) my system is likely overcharging especially when the battery is at full charge.

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I will, first, fit a new Ducati Energia OEM regulator and look for any change. This will be my fourth. They appear to last 34,000-37,000 miles for me, even with the case grounded. That's a cost of just over 1/2 US cent per mile. :nerd:


I see that this regulator is "set" for 14.2 volts with no apparent provision for tapering the charge to the AGM specified "float" voltage (13.4-13.8v).

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I will, first, fit a new Ducati Energia OEM regulator and look for any change. This will be my fourth. They appear to last 32,000-37,000 miles for me, even with the case grounded. That's a cost of just over 1/2 US cent per mile. :nerd:


I see that this regulator is "set" for 14.2 volts with no apparent provision for tapering the charge to the AGM specified "float" voltage (13.4-13.8v).

The regulators I have pulled apart seem to be set for 13.8 Volts. Add to that about half a Volt drop through the headlight relay brings it up to ~14.3.

If you remove the current through the headlight relay the Voltage drop will also be less and the battery Voltage will drop accordingly.

You can measure the Voltage drop if you put your meter from battery Positive to the female connector where the regulator black wire plugs in (with Key On)

I used to see anything from 0,5 to 1 Volt on my VII Sport, and it would drop down a bit if I wiggled the headlight relay,

The earlier 2001 was particularly bad because it went through the NC start relay as well. I eventually gave up on that flakey reference and went for an after market direct connect regulator.


Don't get me wrong I like the Ducati Energia it's so simple, it just suffers from Luigi's poor reference.

I always meant to try a wire from the ECU relay to the black wire. That relay is lightly loaded so it should regulate about 13.8 Volts.

To increase the Voltage back up all you have to do is add resistance in series with the black wire, about 200 Ohms or a small diode will give you 0.6V

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I had promised to take that voltage drop measurement and have yet to.  I certainly will during this foray.  luhbo and I briefly discussed moving the voltage reference, and I would still like to give that some consideration.  At this point, not only is my headlamp on a dedicated circuit, but I'm running numerous LED (not sure how that may be affecting charging reference, if at all.


I did decide to Remove/Replace the Regulator/Rectifier with an OEM R/R again this time (the ever quixotic docc). I'm going to look at grooming the harness so I can R/R the R/R without also R/R the tank. :rolleyes:


I recall when you took those good measurements, Roy. We were wondering why my regulator seems set higher and considered the reference wire voltage drop and the presence of the separate headlight circuit. Yet, the EuroMotoElectrics spec sheet states "Voltage setting 14.2 V / 350 watts."




At this point, I also wonder about increasing the wire gauge of the red charging wire that normally runs to the nefarious melting 30 amp fuse.

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I have a later version of the schematic, I tested it on the bench.

I should point out what I call Battery Voltage on the table is actually the Voltage at the black wire.


I suspect Euromotor electrics are quoting the final Voltage, setting + drop (Voltage at Black wire + Voltage drop)



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Three days later, I have my replacement OEM R/R from EuroMotoElectrics in Colorado, USA. Under $150US. Solid outfit.


I will evaluate to see if I can do the swap without removing the tank. I have my entire wiring harness very closely groomed, so I am not sure I can accomplish that.


Counter to my typical methods, I would like to make only this one change and see if the Battery Light Flicker changes before moving on to consider other modifications to the charging system.


These are the only other things I can think of altering:

1) Larger gauge red charging wire from the regulator to the my 30 amp Circuit Breaker.  (Worth it?)

2) An alternative "Battery Reference."  (But from where?)

3) A "voltage indicator" as luhbo has in service.


[edit /Feb28, 2018: Before installing the new regulator, I decided to fully service my ground connections to the battery and monitor for changes in charging behavior: http://www.v11lemans.com/forums/index.php?showtopic=20152&p=230608]

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As to the Voltage reference just take a 6 ft length of 18 gauge and put a FM bullet on the end, plug the black wire into that, the white wire can connect onto the male pin of the M/FM loom connection, now you can move the reference around to various spots.


Just be aware if you leave it off the battery will go flat. the engine will stop and won't have enough power to re-start, don't ask me how I know this.

I think the drain on the reference is about 12 milliamps.


I have wired it directly to the battery to save time when charging quit on a trip, as long as you remember to disconnect it when stopped it's ok.

I'm not a fan for adding relays but

If you don't have a sidestand switch perhaps use that relay to connect it direct to the battery.

The ECU relay would be another with low Voltage drop, not the one that drives the pump.

The tail-light circuit is on a separate fuse also.


Finally if you want to increase the output Voltage you can calculate the resistance to add in series with the black wire

Voltage / 0.012 Ohms   e.g. 0.5 Volts / 0.012 = 41 Ohms


Really your headlight relay should now be much closer to battery Voltage, you said you have separate H/L relays.


I believe if you can solve the flakey reference the regulator should last the bike out.


Good Luck

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I believe if you can solve the flakey reference the regulator should last the bike out.

This is a noble goal!


No value in increasing the red charging wire gauge?

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  • 2 weeks later...

No there is lots of spare voltage to overcome resistance in the red wire, the ground on the other hand needs to be low resistance because it’s part of the Voltage reference.



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  • 3 weeks later...

I'm rebuilding my negative terminal junction block (a good thing), but suspect my regulator is played up.


Going to be dedicating myself to finding the reference voltage that will let my fourth regulator "outlast the bike."


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