Quick questions - low battery voltage CEL

[Webbie]

As a standard practice, I always plug my Buell (XB12Scg) into the battery tender when I get home from a ride. The last 2 trips home from my work, which is about a 20 mile ride, the check engine light came on. I have the Buelltooth connected so when I got home I checked the error and it indicated a low battery voltage error. Here's the troubleshooting I've done:

I charged the battery with my battery tender, which took overnight, so it really was drained.

The battery IS 10 years old now based on the battery code, so for sure I'm going to change that, but I don't believe it's the root source of the problem...and here's why:

When I put my voltmeter on the battery with the key off, I was getting 13.6 volts

With the key on, engine off, it drops to 12.8 volts

With the bike running, the voltage stays right at 12.8 volts, no matter the RPM's (ran it up to about 4k)

I pulled the side scoop off, and switched the meter to AC volts and tested the stator plug. With the bike running, the AC voltage was right where it should be through the rev range.


So my thought is, it MUST be a voltage regulator issue. Do you guys concur? I KNOW the battery needs to be replaced, but (and I had this argument with my stubborn, dopey, engineer friend who likes to talk more than listen) a bad battery would not STOP the charging system from providing voltage to the battery.....regardless of whether or not the battery would ACCEPT it. Right? If the battery was total crap (which it isn't....it took a charge from the battery tender and started the bike!), it would not stop the Stator and VR from "providing" the 14+ volts at 2,500 RPM's, right?

My thought is to order a new Voltage Regulator (and get a new battery too, just because it's old).


Thoughts? Suggestions? You guys agree with my troubleshooting?



Thanks in advance,

Warner

 

[Silverrider]

10 years old that is very hard to believe ?????? Wow ! You may have volts but you do have cranking amps ? You should do a load test. Either way you are over due for a new Batt ,start there. Warner.
Have you broke in that seat yet ?

 

[TPEHAK]

Your battery is OK if it is cranking engine and keeps charge without battery maintainer (it is probably OK even it does not hold charge because of it can be parasitic draw in motorcycle circuits). Anyway it looks like in your case battery is not the problem. If stator test shows appropriate AC voltage but there is no battery voltage changes at any engine RPM this is problem between stator and battery which is VR plugs, VR wires or VR itself, or wires between VR and battery. My bet is on the VR itself cuz I had same malfunction.

 

[Cooter]

You didn't say what year you have so if it's an earlier bike, check the "77" connector. Its the big plug on the stator output wires thats known to get overheated and fail. Also check the fuse box for a blown fuse, the VR could simply not be turning on.

The battery should be changed, even if it's 'good' for now. A 10 year old battery on a Buell is just asking to leave you stranded. Get a good one, no BS. 220CCA minimum. From Harley, or Deka Big Crank batteries also have a good rep here.

Since your charging system isn't currently working, we'll need to diagnose. Simply put, the stator generates A/C by spinning magnets around wires. This A/C current (3 black wires) goes right to the Voltage regulator (rectifier) where it gets "rectified" to the DC your system and battery need as well as "regulated" to the max of about 14.7 volts. The VR output is the black and red wires that go straight to the battery.

Since you don't currently (PUN bitches!!) have voltage through the system, I would start by checking the output of the stator, it's easy and outlined in the service manual. You can get a .pdf of the service manual from either Buellmods.com or Buelltooth.com.

 

[Webbie]

You didn't say what year you have so if it's an earlier bike, check the "77" connector. Its the big plug on the stator output wires thats known to get overheated and fail. Also check the fuse box for a blown fuse, the VR could simply not be turning on.

The battery should be changed, even if it's 'good' for now. A 10 year old battery on a Buell is just asking to leave you stranded. Get a good one, no BS. 220CCA minimum. From Harley, or Deka Big Crank batteries also have a good rep here.

Since your charging system isn't currently working, we'll need to diagnose. Simply put, the stator generates A/C by spinning magnets around wires. This A/C current (3 black wires) goes right to the Voltage regulator (rectifier) where it gets "rectified" to the DC your system and battery need as well as "regulated" to the max of about 14.7 volts. The VR output is the black and red wires that go straight to the battery.

Since you don't currently (PUN bitches!!) have voltage through the system, I would start by checking the output of the stator, it's easy and outlined in the service manual. You can get a .pdf of the service manual from either Buellmods.com or Buelltooth.com.

Sorry...the bike is a 2008 Scg, so it's got the newer "77" plug.

I realize the battery needs to be replaced, and it will be this weekend. However, it's not the batterie's fault that it's not getting any charge. It charges fine from my maintenance minder trickle charger. And it started the bike, so there is that.

I know how the stator works....and I tested the AC voltage coming from it. It's right where it should be at all of the RPM levels. (took me a while to figure out which plug was the Stator wires....I'm used to there being three, and this one only had two).

So this is what led me to the conclusion that it's most likely the Voltage Regulator. Had the same problem on my other bike (1990 CBR1000 - the original Honda Hurricane) and the VR fixed that as well.

I was just looking for someone to shoot holes in my idea that it has to be the voltage regulator based on my troubleshooting....because I can't see how it's anything else.....

Thanks for all the replies, guys

Warner

 

[Webbie]

10 years old that is very hard to believe ?????? Wow ! You may have volts but you do have cranking amps ? You should do a load test. Either way you are over due for a new Batt ,start there. Warner.

Well, it started the bike so the cranking amps are good enough for that. I'm replacing the battery....no doubt about it. Tonight, in fact. But I don't think that's my problem. I'm reading this date code correctly, right? July of 2007?

 

[user_deleted]

your alternator has 2 output wires because it's a single phase unit. 07 and earlier 3-phase unit.
assuming your battery fuse is good and the female lugs pristine....it in fact is a faulty VR. replace it

 

[Silverrider]

Well, it started the bike so the cranking amps are good enough for that. I'm replacing the battery....no doubt about it. Tonight, in fact. But I don't think that's my problem. I'm reading this date code correctly, right? July of 2007?

View attachment 7843

Wow 10 yrs , amazing. I think average is about 5 yrs.

 

[Webbie]

Wow 10 yrs , amazing. I think average is about 5 yrs.

Yes, I was SHOCKED to see that date code. Haha. New battery will be picked up tonight on my way home from work. Here's the one that I ordered:

https://www.batteriesplus.com/battery/motorcycle/buell/xb12scg/1200cc/2008/cyl10012

Warner


PS - Also ordered a Voltage Regulator from Surdyke. $101 including shipping.

 

[Webbie]

Have you broke in that seat yet ?

Hahaha....define "broke in". It's been on there since I got it from you.....it's never going to be as comfortable as my old CBR though. Haha. I call the Buell my "skateboard". Hard edge commuter/hooligan bike. It's the one I usually ride unless I'm going somewhere far, or want to hold 90+ on the highway. The CBR lives for that.....cruises comfortably at 100.....so I'm told.

Warner

 

[Silverrider]

Hahaha....define "broke in". It's been on there since I got it from you.....it's never going to be as comfortable as my old CBR though. Haha. I call the Buell my "skateboard". Hard edge commuter/hooligan bike. It's the one I usually ride unless I'm going somewhere far, or want to hold 90+ on the highway. The CBR lives for that.....cruises comfortably at 100.....so I'm told.

Warner

define "broke in".

Defined = Fits your A$$ . LOL

 

[Webbie]

define "broke in".

Defined = Fits your A$$ . LOL

Probably as well as it's going to.

Warner

 

[Webbie]

Are you guys ready for this? I took the old battery in for the core charge refund, and had the place test it. So, my TEN year old battery tested GOOD! The guy asked me if I still wanted the new one. Haha. Of course I took the new one, but damn!





Here's a couple photos of the voltage regulator that I'm replacing. The back of it has some cracking it looks like....don't know if that's normal or not, but it doesn't look great.






Finally, does anyone know where to get these type of cable ties? I spent way too much time getting one to release hoping to re-use it, then with the other two got frustrated and said F it and cut them off. Do auto parts stores have these, or are they more specialized than that?

 

[Webbie]

Finally, does anyone know where to get these type of cable ties? I spent way too much time getting one to release hoping to re-use it, then with the other two got frustrated and said F it and cut them off. Do auto parts stores have these, or are they more specialized than that?

View attachment 7848

I guess the part number is 10177, which is a replacement for C0026.02A8

 

[TPEHAK]

I replaced this piece with zip tie. Insert zip tie from top side to the hole, then make a loop around you wires and insert zip tie back in the hole, then lock and tighten zip tie. Done!

 

[user_deleted]

VR is junk. i previously told you that. heat melted the factory insulating sealant.
10177 is nothing more than a push-mount cable tie. available online for cheap. the style of the stud differs slightly but makes no difference as it's hidden when installed. i keep them in stock.