Ducati Monster Forum

Hi  :) 

I recently started to have a problem.   Sometimes when I start the bike  , I hear the solenoid the starter motor turn bust just lacks energie.   when I go home  a tested the battery 11.5v   I charge the battery I'm ok for a couple of days.  I put my other battery in  same problem.    Battery output test  12.3v - 12.4v    (when the battery just ben charged)  If i look into Haynes manuel it should be arround 13.5v -15v

all the connections are fine...  [thumbsup] 


It's like I can go ride it the battery charge for its own use but to start the bike   its not enough.   

Does it looks like I have a voltage regulator problem ?     Its new from last year ca-cycleworks

I'm no electrical expert, but here's my thoughts after dealing with a little bit

You're voltage regulator just controls the amount of charge going to the battery continuously from the stator. It's not really going to determine how much of a charge the battery actually HOLDS.
It's a pretty simple task to run through the whole charging system, and that should really clear up where your issue is.

Here is a handy guide on doing a quick diagnosis of your charging system. You'll need a multimeter.
http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf (http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf)

My thread on a similar issue here may be helpful: http://www.ducatimonsterforum.org/index.php?topic=57133.0 (http://www.ducatimonsterforum.org/index.php?topic=57133.0)

It COULD be a regulator problem. The issue then is, why did you toast another regulator?
The regulator is like a gate for the juice. It has an OPEN and a CLOSED. When they bite the bullet, they either lock up in the open position, which will end up OVER charging your battery (and of course ruining it), or they lock in the closed position, which will under charge your battery.

You could be having a stator issue as well, just not generating enough juice to begin with... or it's OVER generating, which could be why you toasted another regulator.

Either way, that electrosport guide will help you narrow some things down.

The best motorcycle charging system diagnostic procedure is at:

 http://www.triumphrat.net/speed-triple-forum/104504-charging-system-diagnostics-rectifier-regulator-upgrade.html (http://www.triumphrat.net/speed-triple-forum/104504-charging-system-diagnostics-rectifier-regulator-upgrade.html)

While the link is a Triumph site, the author is a well known and respected electrical guru on many motorcycle sites and his procedure has been referenced numerous times.

Start by having the battery fully charged and load tested.  If the battery checks as good, then start the bike and place your volt meter across the battery.  At 3K RPM you should read 13.5 - 14.5 volts.  If not, you have a charging system problem, bad battery connections or a bad ground.  Cory beat me to it, but   http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf (http://www.electrosport.com/media/pdf/fault-finding-diagram.pdf)  is a good guide for the charging system.   That pesky connector that connects the stator to the regulator is a good place to start.  Remind us, year and model bike?

High resistance at a battery connection or ground will cause both charging and starting problems even though the major components are good.  Best way to find high resistance is easiest to find by voltage drop.  http://www.crookedriverwriter.com/index.php?/Automotive-Topics/voltage-drop-testing.html (http://www.crookedriverwriter.com/index.php?/Automotive-Topics/voltage-drop-testing.html)

Brad wrote up a pretty good diagnosis thread too...

http://www.ducatimonsterforum.org/index.php?topic=60660.0 (http://www.ducatimonsterforum.org/index.php?topic=60660.0)

Tanks for all the info's  [coffee]       after checking overything it seams to be a "bad ground"     So I've regrounded the regulator.

And now  at 3000 rpm give me a reading   of 12.6v  for a initial charge on the battery of 11.8v    so it's gain of 0.8v ...     I'm recharging the battery now and I should have a 13.4v gain while at 3000-5000rpm.    the only thing is that multimeter is not that precise.... but still it's an improvement.  

1995 monster 900 [Dolph]

Your battery is a storage device.  Fully charged is 12.6 volts.  Your charging system supplies the electricity to run your bike and to charge the battery.  That is what you are measuring at 3K RPM.  You are undercharging..  If all connections and grounds are good, you need to measure AC voltage from the stator.  Stator good?  Replace regulator. 

stator is A-Ok          after testing .... regulator is the problem   :o    It was "almost" new from last year  [bang]      I'll buy another one whit a indestructible mosfet circuit   [thumbsup]     tanks for all the help  [beer]

Take a good look at the stator to R/R connector since that is a common failure point. If it is okay, the link I included in my earlier msg above has some informative advice re acquiring MosFet R/Rs.

I"ve completely change the connectors long ago and there hare ok it was my first verification since they can suffer from the heat of a bad connection.

I'm amazed by this. You shouldn't be rocking the rectifier/regulators at that pace.
Not sure how you have it mounted, but you may want to look into a TPO parts kit for inverted mounting to get it more airflow... I'd hate to see you spend all that coin on a MOSFET R/R and have it burn out as well...

good luck! electrical issues are always a bummer.

She has an older carbie. Unless she moved it, the R/R is mounted under the lower triple and gets plenty of air.

Oh!

yeap!!  under the the bike  :)