losing charge

[nudemetalz]

Greetings,

 

Having issues with my 80K old '02 V11 Sport.

The gel battery which was 2 years old was going flat so I replaced it thinking it was knackered with one of these new glass-mat batterys.

Unfort it's still not holding it's charge, so I've checked all of the connection etc to no avail.

 

Took it to the shop and they reckon and they checked everyuthing and have guessed that it's the regulator/rectifier.

Now I've read all of the relevant threads here regarding r/r's and they don't seem to be some thing which readily fails.

Anything else readily apparent that I could look for?

 

Any help is appreciated

[Guzzi2Go]

Have you checked alternator/regulator output?

 

Alternator (yellow wires) - 15@1000, 40@3000, 80@6000 V/rpm

Regulator - 14-14.6V

[nudemetalz]

Have you checked alternator/regulator output?

 

Alternator (yellow wires) - 15@1000, 40@3000, 80@6000 V/rpm

Regulator - 14-14.6V

 

Shall do, thanks

[Kiwi_Roy]

The regulator is something I know quite a bit about. The one on my V11 Sport was only charging weakly also so I pulled it apart and analyzed the circuit diagram. I made the mistake of unplugged the headlight relay thinking with less drain on the battery the weak alternator would be able to maintain enough charge, of course now I know this was exactly the wrong thing to do.

 

Alternator Tests

If you unplug the regulator and measure between the two yellow wires from the alternator you will get 60-80 Volts (I can't remember exactly) with the bike running.

With the bike off you will get a good circuit (

 

Regulator Maintenance

In my opinion a bad ground is what causes the regulators to fail, it fools the regulator into thinking the battery voltage is low so it turns hard on and overloads.

Your regulator must have a perfect connection to ground. If it has a flimsy wire under one of the bolt heads I recommend supplementing this with a short jumper to one of the timing cover bolts. I actually drilled a hole in one of the fins and attached a jumper directly to that. At the very least remove it to clean and grease where it touches the chassis

 

Wiring Tests - I assume you have the Ducati Energia

Slip the black / white plug out a little so it's still connected but you can get your multimeter probe on the black wire pin. With the key on you should measure the battery voltage from there to the chassis, that Voltage is what turns the regulator on to charge the battery and tells it when to cut back.

The voltage on this pin comes from the headlight relay via a red/black wire that also supplies several of the dash lights. On most bikes the headlight relay depends on the N/O contact of the start relay, you have a 5 pin relay there don't you?

The red wires connect to the battery via a 35 Amp fuse so you should have a good low resistance from the connector to battery positive. The fuse is something to check also it shouldn't be getting warm, make sure the contacts are tight.

 

Hopefully by this point you have found the problem, if not the next step is to check the regulator diodes, if 3 cases are enough to go by that's what gives out, refer to attached.

 

Regulator Basic - With Notes.pdf

If you find one of the diodes open, don't start hacking into the regulator, it's quite tricky getting on apart in one piece, I have a work around fix.

 

Relay Base Contacts

If you have a loose connection in the base of Start or headlight relay it's possible the regulator is not seeing the correct reference Voltage on it's Black wire but this would result in overcharging not what you are experiencing. Overcharging may cause regulator failure however.

Relay Base Repair.pdf

 

Hopefully this will get you going, if not look for a PM.

Cheers

Roy

[nudemetalz]

The regulator is something I know quite a bit about. The one on my V11 Sport was only charging weakly also so I pulled it apart and analyzed the circuit diagram. I made the mistake of unplugged the headlight relay thinking with less drain on the battery the weak alternator would be able to maintain enough charge, of course now I know this was exactly the wrong thing to do.

 

Alternator Tests

If you unplug the regulator and measure between the two yellow wires from the alternator you will get 60-80 Volts (I can't remember exactly) with the bike running.

With the bike off you will get a good circuit (

 

Regulator Maintenance

In my opinion a bad ground is what causes the regulators to fail, it fools the regulator into thinking the battery voltage is low so it turns hard on and overloads.

Your regulator must have a perfect connection to ground. If it has a flimsy wire under one of the bolt heads I recommend supplementing this with a short jumper to one of the timing cover bolts. I actually drilled a hole in one of the fins and attached a jumper directly to that. At the very least remove it to clean and grease where it touches the chassis

 

Wiring Tests - I assume you have the Ducati Energia

Slip the black / white plug out a little so it's still connected but you can get your multimeter probe on the black wire pin. With the key on you should measure the battery voltage from there to the chassis, that Voltage is what turns the regulator on to charge the battery and tells it when to cut back.

The voltage on this pin comes from the headlight relay via a red/black wire that also supplies several of the dash lights. On most bikes the headlight relay depends on the N/O contact of the start relay, you have a 5 pin relay there don't you?

The red wires connect to the battery via a 35 Amp fuse so you should have a good low resistance from the connector to battery positive. The fuse is something to check also it shouldn't be getting warm, make sure the contacts are tight.

 

Hopefully by this point you have found the problem, if not the next step is to check the regulator diodes, if 3 cases are enough to go by that's what gives out, refer to attached.

 

Regulator Basic - With Notes.pdf

If you find one of the diodes open, don't start hacking into the regulator, it's quite tricky getting on apart in one piece, I have a work around fix.

 

Relay Base Contacts

If you have a loose connection in the base of Start or headlight relay it's possible the regulator is not seeing the correct reference Voltage on it's Black wire but this would result in overcharging not what you are experiencing. Overcharging may cause regulator failure however.

Relay Base Repair.pdf

 

Hopefully this will get you going, if not look for a PM.

Cheers

Roy

 

Awesome information !!! Thank you so much and I will try all of this.

 

Cheers

Chris

[Guzzi2Go]

Thanks, K-Roy, I was looking for these PDFs as I have the regulator in my hands right now and am trying to figure out what is wrong with it.

 

Are you suggesting to bypass the diodes externally (hook them up between yellow and red wires), in the case they are malfunctioning?

[Kiwi_Roy]

Thanks, K-Roy, I was looking for these PDFs as I have the regulator in my hands right now and am trying to figure out what is wrong with it.

 

Are you suggesting to bypass the diodes externally (hook them up between yellow and red wires), in the case they are malfunctioning?

 

Yes, but only if they are open circuit. Its too risky trying to open the case and fix them, I have done 2 successfully but a third the epoxy was so hard I destroyed the circuit board

The diodes are connected directly between Yellow & Red so adding to the outside is simple and can be a permanent fix.

I sent you a PM

Roy

[Guzzi2Go]

Yes, but only if they are open circuit. Its too risky trying to open the case and fix them, I have done 2 successfully but a third the epoxy was so hard I destroyed the circuit board

The diodes are connected directly between Yellow & Red so adding to the outside is simple and can be a permanent fix.

I sent you a PM

Roy

Thanks! Are you talking of "thermal death" if a diode is added in parallel to a working one?

[Kiwi_Roy]

 

Thanks! Are you talking of "thermal death" if a diode is added in parallel to a working one?

Yes, heres a picture of one where both diodes gave out, kindly sent to me by Savomir Musilek all the way from Czech republic.

 

Top left is the diodes one has a lead laying beside it. The other lead you can see on the RH side of circuit board, they have been arcing away for quite a while, the owner probably was getting quite frustrated with low battery charging.

Bottom right are the SCRs

 

This ones quite fixable for a few cents, the diode leads can be re-soldered and a few other parts need replacing. It takes lots of patience to get the circuit board out and no gaurantee, sometimes the epoxy is just too hard. I was really only interested in the case.

[raz]

Yes, but only if they are open circuit. Its too risky trying to open the case and fix them, I have done 2 successfully but a third the epoxy was so hard I destroyed the circuit board

The diodes are connected directly between Yellow & Red so adding to the outside is simple and can be a permanent fix.

I sent you a PM

Roy

Thanks! Are you talking of "thermal death" if a diode is added in parallel to a working one?

When he said "only if they are open circuit" I think he meant it like "only if they are not shorted". Diodes often fail to shortcut, and then you can't add external ones. But this regulator is notorious for having the diodes fail to open circuit.

 

AFAIK there is no problem with paralleling a healthy diode with another one. Right, Roy?

[Kiwi_Roy]

 

AFAIK there is no problem with paralleling a healthy diode with another one. Right, Roy?

 

As I said so long as it's not shorted out it's OK. The ones I have disected the diode part is still OK but the lead has melted off so it's disconnected in effect.

 

Actually since each diode has it's cathode connected to a red wire you could just cut the red wire and run it to your new diode that would be same as internal, neater in fact, I will update my drawing that way.

[Guzzi2Go]

AFAIK there is no problem with paralleling a healthy diode with another one. Right, Roy?

Diodes/semiconductors have negative temperature coefficient, meaning their resistance will drop with increase of temperature. When two slightly different diodes (they always are) are connected in parallel, one will be drawing larger current then the other and therefore heat more. As a consequence its resistance will further drop and it will draw even larger current, thus heating even more. Unless compensated for, it will eventually spiral itself to death, starving the other diode.

 

That's what I meant with "thermal death", and is usually the reason why two 1A diodes are not the same thing as a 2A diode.

[Kiwi_Roy]

Diodes/semiconductors have negative temperature coefficient, meaning their resistance will drop with increase of temperature. When two slightly different diodes (they always are) are connected in parallel, one will be drawing larger current then the other and therefore heat more. As a consequence its resistance will further drop and it will draw even larger current, thus heating even more. Unless compensated for, it will eventually spiral itself to death, starving the other diode.

Yes, that's a very good point but easily worked around, in my work I see semiconductors in parallel on large current loads and series on high voltages.

Its OK to put an external one in parallel with the internal because it's disconnected anyway and if you put two in parallel that are each capable of carrying the full current thermal runaway is not an issue.

[Guzzi2Go]

Its OK to put an external one in parallel with the internal because it's disconnected anyway and if you put two in parallel that are each capable of carrying the full current thermal runaway is not an issue.

I don't think I'll have the opportunity to try that out, as I just, as per your advice, ordered a rectifier bridge. Seems like this is the cheapest/simplest way to obtain a pair of sufficiently powerful diodes. Will keep you posted on how it goes.

[raz]

Diodes/semiconductors have negative temperature coefficient, meaning their resistance will drop with increase of temperature. When two slightly different diodes (they always are) are connected in parallel, one will be drawing larger current then the other and therefore heat more. As a consequence its resistance will further drop and it will draw even larger current, thus heating even more. Unless compensated for, it will eventually spiral itself to death, starving the other diode.

 

That's what I meant with "thermal death", and is usually the reason why two 1A diodes are not the same thing as a 2A diode.

Ah, yes. I assumed adding diodes that can take the full load. My point is there's no reason to hesitate to try external diodes as long as the internal ones are not shorted. I have a regulator that I'm sure has a bad (open) diode but it's intermittent so it looks fine when I measure it. If I ever need that regulator I will try external bridge rectifiers for sure.