2002 LeMans voltage regulator - help!

[Doansci]

2002 Lemans with 28,000 miles and most of its time spent on the dry side of the Cascades.  Ducati Energia regulator.  The charge light only illuminates occasionally.  I have just replaced the old Odyssey battery with a new one.  Battery voltage is 13+ volts after charge, but drops to 12.5 or 12.6 with the key on.  It was also compared to the old battery by the battery shop and meets spec - 450 cca. 

The problem is the regulator works but it seems slow.   Battery voltage will drop when the engine starts and runs - 12.5V or a little less.  If given 2500 rpm the voltage will then jump up to somewhere in the 14 volt range and decrease to roughly 13V as it idles down but if run up to 3500rpm the battery voltage will run up to over 16V.  For a while.  Eventually the regulator seems to find the voltage and regulate it down into the 14V range.  So - it seems to work, but slowly or intermittently.

The regulator is mounted above the horns under the gas tank. (most pictures show it mounted between the horns, but this is not)  I have checked and cleaned the bullet connectors from the regulator to the harness (all seemed good and free of corrosion). I've run a 12 gauge ground wire from the regulator case to the negative battery terminal and cleaned and tightened the ground strap from the negative battery to the back of the transmission. 

The underside of the regulator has greenish potting that has turned brown where the wires enter the case.

I have been reading on the forum that the regulator "senses" the voltage and responds and this one does seem to do that - both initiating charge and, eventually, reducing the charge to less than 15 Volts. 

So, is the regulator working and the wiring harness a mess or is the regulator toast?   BTW none of the relay or fuse contacts under the seat are melted - they all look like you'd expect.

Hope to take this bike on a camping trip next week so appreciate your help and ideas.

Thanks!

Shawn

 

[Lucky Phil]

Look like you need a Reg. The reg should never spike to 16 volts.

Phil 

[audiomick]

I agree with @Lucky Phil

Be aware that if the regulator is defective, it will cook your nice new battery in fairly short order.

[gstallons]

Get you a GOOD new regulator. Not an eBay $19.95 special.  Be advised your charge light can come on if it is overcharging also. These components are cheaper than alternators , wiring harnesses and MORE.

[Doansci]

Thank you.  Previous posts on the charging system describe how the regulator senses battery voltage from the headlight circuit and that resistance can cause over charging.  My thinking was that there might be a poor connection there causing intermittent or slow response by the regulator that might be solved by running a wire from the positive battery terminal to the regulator.  Is this a valid test or crazy talk?

Thank you again!

Shawn 

[docc]

https://www.euromotoelectrics.com/product-p/edl450-voltrect.htm 

[Doansci]

Thank you Doc - it's just been ordered! 

[gstallons]

Don't overthink your problem. You did the right thing . Now , when you get the replacement wire it in hard w/good butt connectors and get rid of the bullet connectors.

[Tomchri]

And me think Kiwi Roy says, DON'T ground the regulator at the battery negative. Good ground from regulator to engine block.

Cheers Tom.

[audiomick]

2 hours ago, Tomchri said:

And me think Kiwi Roy says, DON'T ground the regulator at the battery negative. Good ground from regulator to engine block.

Cheers Tom.

If I recall correctly, the reason for that is that if ground connections elswhere go bad, the connection from the regulator to battery negative could end up trying to be the main ground for the whole wiring system, and get fried.

Edited Sunday at 11:05 PM by audiomick

[docc]

2 hours ago, Tomchri said:

And me think Kiwi Roy says, DON'T ground the regulator at the battery negative. Good ground from regulator to engine block.

Cheers Tom.

 

18 minutes ago, audiomick said:

If I recall correctly, the reason for that is that if ground connctions elswhere go bad, the connection from the regulator to battery negative could end up trying to be the main ground for the whole wiring system, and get fried.

My recollection is that this applies to the small gauge factory regulator ground back through the loom to the battery.

Yet, there is wisdom in making a short, robust ground from the regulator case to the engine/timing chest as long as the main battery ground to the back of the gearbox is reliably serviced.

Comments, @Kiwi_Roy ?

edit:

(Inadequate) factory regulator ground wire after failed main battery ground to rear of the gearbox:

[docc]

8 hours ago, Doansci said:

Thank you.  Previous posts on the charging system describe how the regulator senses battery voltage from the headlight circuit and that resistance can cause over charging.  My thinking was that there might be a poor connection there causing intermittent or slow response by the regulator that might be solved by running a wire from the positive battery terminal to the regulator.  Is this a valid test or crazy talk?

Thank you again!

Shawn 

@Doansci, considering your interesting inquiry, it occurred to me the regulator voltage reference relies on the nefarious Relay #2. What sort of relays are in the relay stack now?

You speak Caig DeOxit? Clean, treat and tighten the terminal stacks on the battery....

[LaGrasta]

As I just went through this, allow me to advise also running a power lead directly to the battery, just as https://www.electrosport.com/ suggests. Until I did this, I could not get mine to work properly.

[docc]

26 minutes ago, LaGrasta said:

As I just went through this, allow me to advise also running a power lead directly to the battery, just as https://www.electrosport.com/ suggests. Until I did this, I could not get mine to work properly.

As in directly through a fuse or circuit breaker?

Admittedly, the factory charging wire from the regulator to the battery is ridiculously small . . .

 

[Speedfrog]

As a replacement for your stock regulator, consider upgrading to a Mosfet type reg.

Shindengen Mosfet regs in particular are the bees knees of motorcycle regulators.

https://roadstercycle.com/Shindengen Mosfet Regulator about.htm