Battery drain on XL883C

[yobbo71]

Just an update. Just dropped the bike off at an auto electrician. He seems to think its most likely a faulty voltage regulator. Thinks the diodes are blown and feeding voltage back to the alternator while the bike is off. (EDIT) I wish I took it to the dealer when this problem started. Bike is no longer under warranty.

What causes a regulator to die? Is it just a random thing? Or something I or someone else did to it?

A Friendly Reminder - Harley Davidson Community

 

[Chopper]

Just an update. Just dropped the bike off at an auto electrician. He seems to think its most likely a faulty voltage regulator. Thinks the diodes are blown and feeding voltage back to the alternator while the bike is off. Damn I wish I took it to the dealer when this problem started. Bike is no longer under warranty.

What causes a regulator to die? Is it just a random thing? Or something I or someone else did to it?

The voltage regulator is a series regulator with shunt control. The circuit combines the functions of rectifying and regulating.
If he's a auto tech and not a harley tech you might want to give him the above info.
Did the milliamp draw drop when he unplugged the regulator?
If it did then you have a grounded stator (bad stator), not a bad regulator.
He can check by just testing one of the stator pins to ground, there should be no continuity to ground at all.
If your battery was over charging or "maybe" not charging then it would be a bad regulator.
Just a guess, good luck

 

[NEWHD74FAN]

When your bike is idling, the regulator is bypassing very little current, most of the low stator output current at idle is consumed compensating battery surface charge lost when starting, the EFI, ECM, TSSM, Headlight and accessories. Once underway, the regulator now must bypass all the excess power produced by the stator at full RPM now, which is about 6-8V (Stator wants to produce 20-24V unfettered), so both are generating heat - lots of it locally...! Why does it burn out...suppose your battery is discharged or has internal shorts, it cannot absorb voltage transients as well, and stator must produce more power into a short circuit on one or more of it's poles so possibility of overheating likely, regulator has to keep excess current under control. Single failure can cascade into burnt stator or overheated regulator. If you are replacing the regulator, make sure you check the stator with ohmmeter like Chopper said and drain the gear lube to check for burnt smell.

 

[Chopper]

I found this milliamp draw flow chart in a 2008 Sporster Electrical Diagnostics Manual, thought it might help?

 

[yobbo71]

Ok this is weird. I got it back from the auto electrician, he even had his friend look over it who works at the Harley dealership here in Adelaide.

They couldn't find anything wrong with it. He checked the diodes in the regulator, they were fine. He did a milliamp draw test and his came out at 0 draw except when the little red key flashed then it went to something like 0.7.

Nothing like the 85 milliamps I was getting before.

But now the thing is the bike is no longer losing charge. Its been over a week since I last rode it and it is still starting up just fine. Before it would be dead in just 2-3 days.

Is it possible while they were unplugging and plugging things back in they fixed a dodgy connection?

Like if the main 30A fuse doesn't have a good connection can that cause a current draw when the bike is idle?

He only charged me 40 bucks for looking at it. They were checking it out for about 50 mins.

 

[NEWHD74FAN]

Sometimes when mating and unmating connectors you can clear problems with 2 adjacent pins being unshorted when pulled apart...the key is how did they get shorted together in the first place. The other possiblility is the wiring may pass through a metal wire loom or frame member or sheet metal cutting insulation and grounding out wires beneath. Since your troubleshooting probably disturbed about every string of wiring on the bike. Hint, rule #1 when troubleshooting, disturb things as little as possible isolating one thing at a time and if okay THEN move on. Likely the local short was corrected by moving the wire, which unfortuately is likely temporary cause it was likely only moved a few tenths of an inch from shorting.