Charging system

[Tom M]

Can anyone tell me if there's a spec for what voltage I should be seeing at the battery at various RPM? Would those readings be dependent on the condition of the battery?

 

I installed a new battery a few months back because my 4 year old battery seemed to be struggling to spin the starter. Whenever I tried to start the bike after it sat for a week the solenoid would click but the engine wouldn't turn over. I had to hit the button 2 or more times before it would spin up. I thought maybe the battery just wasn't holding a charge since it was 4+ years old. My on board volt meter showed the charging circuit was working when I was riding with 13+ volts, and the resting battery voltage was about 12.5 volts. I decided to change the battery out after I had a hard time getting the engine to turn over in the middle of a day trip. I tried to have the old battery load tested but my local auto parts store said their tester would overload a motorcycle battery.

 

Since I've installed the new battery it's been fine up until last night when the same old symptom returned. I have a voltmeter installed on my bike and I am not seeing anything greater than 13.9 volts max when riding so I'm wondering if I have a charging system problem, a starter problem, a battery problem, or something else. It seems to me that I used to see over 14 volts when riding but I can't be positive on that.

 

Suggestions are welcome...

[gstallons]

Tom,

I am going out on a limb here, if your bike will show 13.9v with the engine running (@ 1500 rpm) it should be o.k. A fully charged battery will be 12.65 or a little more at rest.

Your riding habits might not be allowing the battery to be sufficiently charging.

What brand battery did you purchase? Return it and explain what is going on to see if you can get another one.

[GuzziMoto]

The voltage you see depends on what the regulator/rectifier is set for. That is typically just over 14 volts (14.1 - 14.2). If you are seeing 13.9 volts, that could be an issue or it could be that your meter is slightly off. I would try another meter to confirm the reading. If it does check out that it is indeed 13.9 volts, you regulator rectifier may be going bad. Check the connections to confirm their condition and clean as needed as well. It could be a duff replacement battery but I would check other options first, as the odds of two batteries exhibiting the same symptoms points to a charging issue.

[Kiwi_Roy]

 

Suggestions are welcome...

You may have a bad regulator, heres a simple test you can do.

I have dismantled 3 Ducati regulators, the common fault seems to be the diodes come unsoldered, the symptoms are weak charging.

It's quite easy to check the diodes because they are wired directly to the yellow and red wires.

If you have a multimeter with diode test put Red terminal on each yellow wire, Black terminal on red wire and you should see somewhere between 0.4 - 0.6 Volts.

If you don't have the multimeter you can use a battery and ammeter or small lamp the ammeter should indicate or lamp should light up if the diodes are OK.

(Battery positive to Yellow wire, Red wire to ammeter (lamp), ammeter (lamp) to battery negative)

If you don't get a circuit through one of the diodes or it's erratic charging will be weak.

Because the diodes are wired directly to Yellow & Red wires it's possible to hang another diode on the outside in parallel as a temporary fix.

I successfully opened up my regulator and soldered the diode back together.

Roy

Regulator Basic.pdf

[mznyc]

Tom

I had similar symptoms(struggled to start) and ordered a new battery.While waiting for the battery many suggested that the starter may be a problem so I opened her up and found a bunch of gunk on the the plunger in the solenoid.Cleaned her up and no problems starting and new battery still sits on shelf and year and a half later.I have to pull the starter to access the pawl spring this week so may be time to clean her up,...

[Tom M]

OK, here's what I got for voltage readings taken with a good meter vs the cheapo gauge on the bike. I put the on-bike gauge readings in [brackets]. Good call on the gauge inaccuracy GM.

 

cold key off [12.6] 12.6

 

key on no run [11.9] 12.1

 

1100rpm [12.7] 13.0

 

2500rpm+ [13.8] 14.0

 

I never see more than 14.0 volts at the battery. Is this a problem or within spec?

 

I also measured 11.5 mA draw on the battery with the key off. Anybody know if that is normal? The volt/clock/thermometer gauge probably pulls a little current above whatever normal is.

 

Michael, I did disassemble and clean my starter solenoid over the winter after it was suggested here that might be why I was having some starting problems last year.

 

I didn't check my regulator connections yet but I cleaned and lubed them when I replaced the regulator a few years back so they should be OK, but maybe I should take a look anyway. The replacement reg is the same unit as stock; Ducati. I'll try the test that Roy suggested when I do if my meter is capable.

 

Both my old and new batteries are Odyssey PC545 Gene. I bought the new one on-line so I probably won't be returning it. Maybe I'll just keep an eye on the situation for now and dig in further if it gets worse.

 

Thanks for the help guys.

[Kiwi_Roy]

Heres a few more tips, I did some tests after repairing my regulator.

Charging Circuit.pdf

[Murray]

You should see 14.6 volts plus or minus 0.2 volts @ around 5000 rpm it shouldn't get any higher after that. Things to try instead of testing directly across the battery test between the positive of the battery and a good metal earth, engine ,voltage regulator case etc. If there is a significant difference between across the battery and the direct earth you have a dud earth. So remove the regulator bolts give them a good clean as the regulator uses the bolts as earth. Also where the negative lead bolts onto the frame clean tight free of corrosion and a good metal to metal contact.

 

If there isn't much difference between the frame and the negative terminal of the earth it might be worth chasing the charge line through the loom and check any connectors it runs through again clean, free of corrosion. Some charge lines run directly onto the starter motor power lead so check that connection as well (drop the negative lead off the battery when messing with these ones otherwise you may end up arc welding).

[docc]

I'm thinking my ground (earth) lead from the battery goes to the gearbox, but not the frame.

 

I've never gotten over 14.0 vDC, either new or with new regulator and new stator; and with all the connectors rubbed up and a frame strap from the motor. I've always made do with 13.6-13.8.

 

You lucky chaps with 14 v must be able to power up some toasty heated jackets and such!

[Murray]

14.6 is the specs out of the 1100 sport workshop manual. I don't run any electrical accessories although the headlight is hardwired on.

[Tom M]

That's interesting Doc. I think I used to see more than 14 volts but I'm not positive. I'd love to know if the spec for the V11 is the same as Murray's 1100 Sport. Murray, do you know if your bike has the same alternator and regulator (Ducati) as the V11? I don't recall seeing any charging spec in the V11 manual. Anybody else out there ever take any charging measurements?

 

Any more diagnosis on my bike will have to wait a few weeks. I'm heading for a cabin on a Maine lake in a few days so I hope it doesn't act up while I'm far from home. At least I'll have a trailer handy. Got to bring the bike along with the wife, kids, kids friends, and a couple kayaks. This is what my driveway will look like Saturday morning...

 

[docc]

That's a beautiful sight! I can't believe you are taking your basketball goal with you on top of the kayaks. What a dad!

 

My Workshop Manual says the regulator should maintain battery voltage between 14-14.6 volts. (2000 V11 Sport)

[fotoguzzi]

That's interesting Doc. I think I used to see more than 14 volts but I'm not positive. I'd love to know if the spec for the V11 is the same as Murray's 1100 Sport. Murray, do you know if your bike has the same alternator and regulator (Ducati) as the V11? I don't recall seeing any charging spec in the V11 manual. Anybody else out there ever take any charging measurements?

 

Any more diagnosis on my bike will have to wait a few weeks. I'm heading for a cabin on a Maine lake in a few days so I hope it doesn't act up while I'm far from home. At least I'll have a trailer handy. Got to bring the bike along with the wife, kids, kids friends, and a couple kayaks. This is what my driveway will look like Saturday morning...

 

your a lucky guy and a great Dad to do that!

 

[raz]

14.6 is the specs out of the 1100 sport workshop manual. I don't run any electrical accessories although the headlight is hardwired on.

Yes but that is a curious spec as I believe the spec for the OEM regulator itself is 14.2 volts. Very Guzzi-ish!

 

I have an onboard volt meter and it's more or less pegged at 14.0 volts, idling or not. I have a high idle though, closer to 1500 rpm than 1000.

 

I'd love to know if the spec for the V11 is the same as Murray's 1100 Sport. Murray, do you know if your bike has the same alternator and regulator (Ducati) as the V11?

They use the same one.

[Kiwi_Roy]

Anybody else out there ever take any charging measurements?

Hi Tom,

Yes, I took some readings off my V11 after re-building the regulator with a new Yuasa battery. If you look back up the thread at my previous post you will see a pdf attached.

Regards

Roy