charging system blown fuse

[dtcohen]

Hi All,

I am still working out the bugs on the 2005 xb12r that I recently purchased. Once I got it running well I started to suspect that the charging system wasn't functioning properly. I checked and sure enough the bike wasn't charging the battery. I started going through the troubleshooting steps and when I unplugged the stator connector I noticed that the pins in the connector were not seated properly and had pushed back in the connector body. I fixed that, and put everything back together. I re-checked and the bike seemed to be charging correctly. Yesterday I checked it again and the battery was down to 10.5v and it wasn't charging. Looking around I found that the 30amp fuse beside the battery was blown.

Would a bad voltage regulator cause this fuse to blow?

Thanks,
Daniel

 

[user_deleted]

Hi All,

I am still working out the bugs on the 2005 xb12r that I recently purchased. Once I got it running well I started to suspect that the charging system wasn't functioning properly. I checked and sure enough the bike wasn't charging the battery. I started going through the troubleshooting steps and when I unplugged the stator connector I noticed that the pins in the connector were not seated properly and had pushed back in the connector body. I fixed that, and put everything back together. I re-checked and the bike seemed to be charging correctly. Yesterday I checked it again and the battery was down to 10.5v and it wasn't charging. Looking around I found that the 30amp fuse beside the battery was blown.

Would a bad voltage regulator cause this fuse to blow?

Thanks,
Daniel

yes daniel it would. the 2 tell-tale signs of a faulty VR is a blown battery fuse and/or non-charging issue. your firebolt has the 30 amp inline fuse in holder as part of the harness while the X and S models have the 30 amp battery fuse contained within the fusebox. if your vaunted "77 connector" has been sorted and repaired as you mentioned and the problem remains it is in fact the VR.

 

[dtcohen]

That is what I figured. The connector looks like the factory style connector, but there is a splice on the regulator side that makes me think it has been replaced at some point. It didn't appear to be melted or corroded.

Is there a preferred replacement regulator? It seems like the only new exact replacement is this one:
https://www.denniskirk.com/2001606.sku?utm_source=google&utm_medium=cse&gclid=EAIaIQobChMI8vnjpIqY1QIVyKoYCh1akQc_EAQYASABEgKeo_D_BwE&ad=45713338237

Is there a better retrofit option? Maybe from another bike?

 

[dtcohen]

Is there a way to test the regulator? I have seen a few youtube videos on how to test the diodes, but some say that this isn't a definitive test.

here is the test I am referring to:
https://www.youtube.com/watch?v=F8EjV0IjW9Q

 

[dtcohen]

Here is a pic of one side of the connector. The shiny stuff is di-electric grease that somebody has put in the connection. Note the crimp connectors next to my fingers.

 

[user_deleted]

the service manual covers most of this but in essence my experience shows these diode as well as ohms/resistance VR tests aren't worth a ****. your charging system in its entirety only has 4 components MINUS any wiring:
1-fuse
2-VR
3-alternator/stator
4-battery
tests are simple as follows:
unplug stator as per manual and test the AC voltage output. the stator is nothing more than an automotive style alternator with the rotor flying around the outside of the fixed coils as opposed to automotive that has the rotor whirring around inside the fixed coils which are part of the housing. make sense?
at approx. 2500rpm you should see vicinity of 47-51 AC volts as per my memory. that is your stator test.
if ok plug all back together and do the simple battery test which is: @ approx. 2500rpm you should see 13.2-14.4 DC volts at the battery terminals. all done with simple multi meter.
your other question? which VR as replacement? shop around for OEM. a few guys on here have experimented with less costly sportster VR which in fact does work BUT the wiring loom needs to be lengthened, a special mounting bracket and hardware fabricated.....utter waste of valuable time. i recommend OEM and be done with it.
having said all this just cut to the chase: if your battery consistently dying from lack of charging voltage and the stator test satisfactory....it's the VR.
if you are burning out light bulbs, frying components, blowing the battery fuse....it's the VR. can't make it simpler than that.
IMPORTANT: the 03-07 VR's same being 3-phase with specific plugs. 2008 and up are single phase with different plugs than previous. BE CERTAIN to order/purchase the correct VR

 

[Cooter]

You got this covered perfectly Lunatic, I'll just be on my way

dtcohen: You're in good hands and should be riding in no time:up:

 

[dtcohen]

I will check the stator AC output when I get home.

 

[dtcohen]

I checked the stator AC voltage output and it is good. The problem is definitely the regulator. Is the best option an oem replacement or is there a more modern or reliable regulator from another bike that could be used? It seems like any regulator would work. They are all 3 phase AC in and DC out.

 

[user_deleted]

read my post in its entirety where i resolved this for you. went thru all this. there's 95,000 assorted VR's that will "work" providing you're willing to change plugs, lengthen harnesses, procure proper mounting hardware, fabricate mounting brackets, ascertain that the output is in the 36 amp max range, that it has sufficient cooling fins/heat sink to work at the standard XB mounting location, etc etc etc.
if you like to actually ride buy oem and get it over with. if you like to spend weekends in your garage fabricating and hoping something else might do the job then............................