[skippy344!]

Hello Folks,

I am still in diagnosis mode, but have questions to be answered before I move forward.

'06, new AGM battery 13.0V from the shop.
Starts fine, and at cold idle (1500RPMs) the voltage reads 12.65v on VOM.
If I increase the RPMs to say 4000RPMs, I see that I now have 13.0V across the battery.

So, at warm idle of say 1250RPMs, the battery is not charging on my bike.

Is this normal for my FJR?

Do I have to keep the RPMs at or above 4000RPMs while riding, to keep the battery charged?

Thanks,

 

[Oldjeep]

In general charging voltage should be closer to 13.7 minimum for a 12v battery.

 

[Oldjeep]

Just as a reference, my bike is at 13.6 at cold start idle. My battery is 13.2 with bike off, but it is a litium battery and they have a higher resting voltage.

 

[skippy344!]

Hi Chuck,

At what idle?

Are you saying your voltage is reading 13.7v at idle?

 

[Oldjeep]

Hi Chuck,

At what idle?

Are you saying your voltage is reading 13.7v at idle?

Hooked up the voltmeter to my battery tender lead, started the bike and it immediately reads 13.6V at idle Bike hadn't been started in several days.

If you mean how many RPM? Dunno, I'd have to start it up again and look

 

[skippy344!]

Well, Damn... Mine does not...

Off voltage is 12.97 and idle is 12.65...

 

[skippy344!]

OK, I checked the stator circuits. all are 0.2-3ohms. It is 98°F here, currently.
I stabbed test leads into the connector that goes to the battery, from the voltage regulator. Off 12.96v. Running 13.7-14v. Sounds good right??

Went back up to the battery to measure voltage... 12.65v running... FML...

 

[jasonm.]

idle should be 1000-1100rpm...at that rpm expect at least close to resting voltage. Once you get to 2000rpm the volts should climb to approx. 13.7+ @3000. My voltmeter also varies significantly readings up/down as rpm changes . Make sure your meter leads are good. Check on ohms and cross them...wiggle wire leads. see -0- or only a few tenths of an ohm

 

[skippy344!]

Hi Jason,

Since I have the Ivan ECU mod, my warm idle is set to 1250RPMs. And it is consistent.

I am using a Fluke 87 True RMS VOM with new leads.

The running voltage right at the reg/rec, is 13.7-14v. But at the battery terminals, it is 12.65v.

I ohmed out each lead, from the reg/rec to the battery. 0 ohms, and full continuity, both pos and neg.

Cleaned and checked the 50amp main fuse. Looks and test good.

 

[Oldjeep]

Sounds like battery is junk or you have some bad wiring somewhere.

 

[jasonm.]

I also have a fluke 101 scope meter for work, sounds like to voltage is not making the trip...something is giving a major draw or resistance. Check spiders ...?

 

[skippy344!]

Oh yeah. All spiders are good, but this circuit does not have a spider in it.

I ordered a Rick's Motorsport Rectifier/ Voltage Regulator.
I will see if it pushes the charge up the wire!

 

[1911]

Watching

 

[skippy344!]

1911, are you having the same issues?

 

[bounce]

A note about the bike's charging ability. At idle (and slow crawl) it will be in a state of discharge since the system is max-rated at higher RPMs, so it's not unexpected. If you're talking about the equivalient of load-testing the battery, then that's a different thing. It's this discharge state that is problematic for parade escorts (but mitigated with the spurts of higher RPM to pass everyone on the way to the next roadblock).

IOW: Not a charging system like a car (or like most BMW bikes have) that keeps the charging output consistent regardless of RPM.

One thing I wondered about (but may have missed) was v drop across any connectors in the circuit.

 

[skippy344!]

OK, an Update...
I got my Rick's MotorSports OEM Regulator/Rectifier, for Lead batteries yesterday. It is really quality made!!
I plugged it in, and observed the same results: Voltage at the regulator, 13.7v, voltage at the battery 12.61v. Damn...
Plugged the old regulator/rectifier in, 13.7v at the regulator, 12.61v at the battery.
So, my issue is Not my regulator.

I did a stupid thing but learned something! When I was swapping the two regulators, I had both unplugged and started the bike for some reason, and realized that I did not have Either devices plugged in. The bike started and ran! LOL Voltage across the battery was 12.01v!


So next steps...
I am going to build a parallel test wire set from the voltage regulator, to my battery, bypassing the wiring on the bike. I want to see what the voltage will be then. I am expecting it to be 13.7 at both ends.

At this point I have become a parts swapper, and may order the ElectroSport Stator, with the enhanced windings.

With the bike going on 17 years old, and 42,000 miles, it may not be a bad thing to update the charging system anyway.

I willu pdate when I have new results.

 

[passx]

Greg, when I start my 14 I always check the voltage on my battery tender volt meter that I have wired into the battery (Oe 🤞) it reads at 14.2volts. That’s on the high idle and then the 1100rpm normal idle.

i realize that the “Battery Tender” display may not be the most accurate but my Fluke VOM always so far agrees with it. I think at this point I’d pull the battery and take it someplace and have it load tested to see if it’s up to snuff.

As a side note, the people at Ricks are nothing short of top notch ! I got to talk to Rick himself who helped me diagnose a problem I was having on my 86 Sei Wing years ago and he was nothing short of fantastic, great guy !

 

[skippy344!]

Thanks for the input Steve!! Yeah, I might take the battery up for an external load test. It never hurts to do that, to eliminate a possible contributor. I would love to see 14v at startup across my battery!

Yeah, I have relied upon and trusted my Fluke 87 True RMS VOM for 30+ years.

All of my crazy racing buddies use Rick's performance stuff.

I will update as I progress.

 

[SkooterG]

Voltages on my FJRs that have had Datel voltmeters have always been 14.0 - 14.2 volts, even at idle. Maybe dipping to 13.9 just after a start. What I did consistently notice is that as the bike and ambient temperatures warmed up, voltage would decrease slightly. Say from 14.15 to 14.05 or so.

My '09 had an issue where charging voltage was slowly degrading. In the low to mid 13's (volts) I took it to a dealer and they said all was fine. But, I knew it wasn't. Anywho, I can't remember all the details but a fellow forum member at the time let me know about a problem affecting a small amount of Gen II bikes. IIRC, it's the connector where the wires from the stator plug into the regulator. A fix was to run a bypass. I'm sorry, I just can't remember the details. Getting old is a bitch. But after I installed that new bypass wiring everything has been good for the last 100k miles and many years. You might try searching on FJRForum,com. That was where all the good tech info was back then and where I got mine assistance.

 

[SkooterG]

Found it! Lots of good information here.

Fix for Degraded Wiring From R/R to Battery on Gen II FJRs.

I had it slightly wrong. The problem lies with the bad wiring or connector from the Regulator/Rectifier to the battery.