Jump to content

30 amp fuse failure


Go to solution Solved by docc,

Recommended Posts

Marty, can you explain this further to me (I'm not sure what you mean by "above.":

 

"If the regulator ground is above battery ground, . . ."

If the regulator is not perfectly electrically connected to the negative ground of the bike, then there can be electrical resistance in the connection.

Resistance can be caused by rust in steel, oxide on aluminium, tarnish on copper. Age, vibration, and weather make electrical connections develop resistance.

In a 12 volt system, resistance matters a lot.

Imagine your regulator is rectifying the AC voltage coming in from the alternator, and regulating the output voltage to say 14 V, and outputting 20 amps to the bike & battery.

 

Now add 0.1 ohms of resistance between the regulator body and the battery negative terminal. That is a tiny resistance, but it makes a difference.

 

Ohms law says E=IxR. Voltage = amps (current) times ohms (resistance)

0.1 ohms x 20 amps means the regulator ground is 2 volts above ground. The regulator is happily putting out 14 volts, but the positive lead is now at 16 volts relative to the true ground.

 

Imagine what would happen if there was even higher resistance to ground. Diodes fry, fuses & wires melt, battery gets hot.

It is possible that voltage regulators get replaced when the problem is poor grounding. Just bolting in a new regulator can disturb the corrosion underneath to get a better ground, for a while.

I believe that mechanical scraping, wire brushing, rubbing with scotchbrite, then assembling with grease is the best way to make good connections. The metal faces of connections must be oxide free (shiny), and I suspect that most electrical cleaning sprays are not active enough to do the job properly.

Very few multimeters can detect resistance below 0.5 ohms, so you just have to do the tedious chore of disassembly and mechanical cleaning as a 100,000 km maintenance task. :unsure:

  • Like 1
Link to post
Share on other sites
  • Replies 128
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

After reading docc's original post on this I liked the idea he had and the way he did it so I went out and looked at the 30 fuse receptacle on my Greenie , even though it was still functioning  it was

Gentleman, I want to thank you all for all of your insight, education, and encouragement. Let's face it, what I'm posting isn't "rated" for anything.   *Entertainment Value Only*  

If the fuse looks ok check the connectors from the alternator to the reg/rec for overheating

Posted Images

The regulator on mine was mounted to the horn bracket which in turn was bolted to the chassis.

I could see no sign that Luigi had given any thought to removing paint from the regulator to bracket or bracket to chassis connection.

I haven't bothered to measure the resistance of the black wire back to the negative.

I suspect when the bikes are new they may get an accidental good ground but as Marty says after a few years it falls back on the small black wire and the battery loses Volts.

Voltage drop between regulator case and battery is critical, the red wire could lose several Volts with no effect

 

Electricians measure low resistance using what's called a drop test, no, we don't throw it on the ground, you pass a known current through the resistance and measure the millivolts drop. It's actually quite easy to do all you need is some way of passing a steady current through the resistor, I use a headlight bulb and a 12V battery and measure the current on the 10 Amp range, for example it measures 4.6 Amps then measure the Voltage drop across the resistance, suppose it's 7 millivolts

Calculate using Ohms Law   7 mV  / 4.6 Amps = 0.0015 Ohms.

The trick is to measure the mV on the right side of the joint because the mV drop is high across the current connections,

 

Using this idea you can then make a shunt from just a piece of wire that can measure over 100 Amps, for example the starter current 7.66 inches of #12 will give you 1 millivolt per Amp and measure 150 Amps for a few seconds before it gets too hot.

  • Like 1
Link to post
Share on other sites

Sounds like a good possibility that my once-upon-a-time shiny, sealed grounds and connections have *aged out* and need a fresh round of meticulous attention.

 

I see a tank coming off in my near future . . . :luigi:

Link to post
Share on other sites

I like DeOxit gold. I think they call it gold because of the price.  It only costs a little more to go first class, though.  :huh2:  Probably overkill for a Guzzi.

Just the same, I've fixed a ton of electrical problems with it. The Kid fixed a $5000 relay on a helicopter.. :luigi:  :grin:

So many times, it's just a little corrosion and DeOxit cleans it up and keeps it clean for a year or so. Oh. Doesn't affect plastic like a lot of contact cleaners. 

I could sell the stuff..

Link to post
Share on other sites

 

 

I could see no sign that Luigi had given any thought to removing paint from the regulator to bracket or bracket to chassis connection.

You see, that is Luigi's plan. If he doesn't grease the steering head bearings, everything on the front end is grounded through them.  :oldgit:

Link to post
Share on other sites

I think the Ducati Energia series type regulator might be partially to blame for the heating

The later V11's have the "Shindengen" (shunt type?) regulator. Do these V11's have problems with the 30A fuse, as we with the "Ducati" regulator do? I have had this year a LiFePo -battery installed, and I believe it makes things worse in combination with the Ducati Energia regulator, because it can take a lot of current in the beginning (but you save 4 kg:s of weight).

Link to post
Share on other sites

I have a theory that the shunt type regulators don't put out such high spikes of current, they can switch off half way through a cycle by shorting out the alternator whereas the Ducatis have to wait until the next half cycle before they disconnect, they have no control over the Voltage mid way through the cycle.

 

We have all seen the open circuited alternator reach 80 or 90 Volts open circuit.

The shunt type will short out the alternator once it goes over Voltage setpoint

The Ducati can't restrict the Voltage and it cannot disconnect until the Voltage goes past it's peak and drops below about 14 Volts

 

To put it differently the shunt type clamps the Voltage from going too high effectively controlling the current.

The Ducati disconnects the battery for a few cycles after the fact, it has no control over the current.

 

I have an Electrosport ESR510 on my 01 not because I don't like the Ducati but because I got sick of the flakey Voltage reference from the headlight circuit

The early VIIs had two relays in series with the headlight, the later ones only have one.

 

I would go with one of the Shindengen ones if I was doing it again

Link to post
Share on other sites

 I got sick of the flakey Voltage reference from the headlight circuit

 

Even with my headlights on a separate circuit, my Ducati Energia charges at 14.2 vDC. I have some voltage and temperature data that I'll post later this evening.

 

But, regarding reference voltage, would it be decidedly better to supply a reference wire directly from the battery or some switched source such as the Fuse 8 circuit?  I mean, mine seems to be working, but I agree that the factory reference location seems dubious.

Link to post
Share on other sites

If you have headlamp relays fed directly from the battery the reference is more stable.

By Ohms law it makes little difference if the resistance of the old headlight circuit is 0 or 10 Ohms at just a few milliamps, a huge difference at 5 Amps.

 

Lately I have been suggesting the Voltage reference could come from Relay 4

 

 

BTW the Electrosport ESR510 has it's own set of problems, I found that over the winter even 0.3 mA will drain the battery so I stuck a fuse in it to disconnect. Come spring I forgot to put the fuse back and took off for a test drive, next thing I know the battery is going flat. Put the fuse back in and bump started, next thing it went flat again, how can that be?

Damned wire fell off.

Link to post
Share on other sites

If you have headlamp relays fed directly from the battery the reference is more stable.

By Ohms law it makes little difference if the resistance of the old headlight circuit is 0 or 10 Ohms at just a few milliamps, a huge difference at 5 Amps.

 

Lately I have been suggesting the Voltage reference could come from Relay 4

Pin 86 of Relay 4 (ECU Relay) would be the same as the (Run Switch) feed to Fuse 8.

 

Looks like 87 has a more direct path (through Fuse 1) to the battery. Is that where would you come off of Relay 4 for voltage reference?

Link to post
Share on other sites

All right, so, I collected some *data* . . . but, remember, I'm a bad scientist. Dr. Venkman and I go way back. :unsure::nerd:

 

I don't think I have an overcharging issue (in fact, I love these voltages):

 

              24 hour OCV (Open Current Voltage)                              12.88

              Ignition on/ low beam                                                      12.21

              Cranking the starter                                                         10.80

              Idle (~1250 rpm +/-)                                                         13.10

              2200 rpm and up                                                              14.20

Link to post
Share on other sites

Using an infrared temperature reader, I collected readings from all the fuses and relays. Again, my Relay 3 (regulator/ charging/ 30 amp) is external to the fuse block and has been converted to a "full size" MAXI fuse. Temperatures were read after riding 10 miles then idling for a few minutes.

 

 

           Fuse                           Fº  /   Cº        

              1 / ECU                   99  /   37

              2 / Fuel Inj/ pump   105 /   40,6

              3 / Reg  30 amp      105 /   40,6   

              4 / Ign  switch          99  /   37

              5 / Lights,etc            94  /   34,4

              6 / City lights etc      96  /   35,6

              7 / Turn signals         95  /   35

 

           Relay                                                  

             1/ Start                      93  /  34

             2/ Lights etc            125 /  51,7

             3/ "neutral"              114 /  45,6

             4/  ECU                    134 /  56,7

             5/ Fuel Injection       161 / 71.7

 

 

 

Seems to me, and I consulted Dr. Venkman on this :rolleyes: , if anything were going to overheat, it would be the Fuel Injection Relay. That one is hot enough not to stick to your lips . :o                                                                                          

  • Like 2
Link to post
Share on other sites

 

If you have headlamp relays fed directly from the battery the reference is more stable.

By Ohms law it makes little difference if the resistance of the old headlight circuit is 0 or 10 Ohms at just a few milliamps, a huge difference at 5 Amps.

 

Lately I have been suggesting the Voltage reference could come from Relay 4

Pin 86 of Relay 4 (ECU Relay) would be the same as the (Run Switch) feed to Fuse 8.

 

Looks like 87 has a more direct path (through Fuse 1) to the battery. Is that where would you come off of Relay 4 for voltage reference?

 

Yes 87 of relay 4, it is almost direct from the battery, I would take it thru a small fuse say 1 amp to the black wire of the regulator.

BTW if the battery Voltage is a bit low without the normal Voltage drop from the headlight circuit add some resistance in series with the black wire so the regulator has to raise the Voltage to compensate,

you could even make it adjustable with a small pot. I think the black wire draws about 15 milliamps but measure it to be sure then you can calculate how much resistance to add

1 / 0.015 = 66 Ohms per Volt, a 20 Ohm would raise it by 0.3 Volts etc.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...