Charging system, Gen II, is it?

[Joel Rappoport]

Evenin' Folks. I've searched through past threads but come up empty and could use some help.

I'm on a new '09 that I've put 2,000+ miles on in the past two weeks and think that I have a charging system problem.

I'm running a Datil voltmeter off of a switched relay from the battery which agrees within 0.1 vdc with my fluke meter measuring the same point.

During normal running I'm seeing 14.1 volts at anything over 2000 rpm. OK so far.

I've noticed that while riding the voltage is solid at 14.1 until I hit my PHID lights. Adding that 85 watts pulls the voltage down to 13.6 (this is after the ballasts warm up and the voltage settles in). If I add my heated jacket for another 50 watts I'm at 13.2 volts. This is while riding at sustained speeds and loads. I haven't added any more load since I figure 13-13.2 is barely charging.

I originally found in a related topic here that the FJR needs around 225-250 watts to run the bike and standard headlights which should leave 340 watts for farkles, or a bit less if the alternator isn't turning at high rpms. Would anyone enlighten me as to if it's 'normal' for the voltage to drop this much with such a small additional load or where to start looking for a bad connection or other Gen II problem?

My reference for this is that I rode a BMW R60/6 for 34 years, the last ten with an aftermarket 450 watt alternator. The "normal" load on the R60 is considerably lower due to the lack of ABS, fuel injection and such butt I have put hundreds of thousands of miles on it and never pulled the output below the set-point of 14.5 volts. I've run it with the always-on HID low beam, PHIDs, two 55 watt fog lights, 100 watt electric jacket, 25 watt gloves, GPS, extra rear lighting all on at the same time and always maintained 14.5 volts.

Any help would be appreciated.

 

[SkooterG]

This is a tough one Joel, a big gray area, but your Datel readings seem a bit low to me.

I've got a Gen I producing 100 less watts than your Gen II. With PHIDs and 90 watt WarmNsafe liner I am at about 13.4V. Which is the minimum IMHO. 13.0-13.2 is too low.

With your 100 extra watts, and only a 50 watt liner, you should be seeing higher readings. If I recall correctly, my Gen I with only PHIDs on (after ballast warm-up) is reading about 13.8V

BTW, PHIDs are more likely closer to 100-110 watts total.

Still, something seems wrong either with your charging system, or either the PHIDs, heated liner, or something else that is drawing more power than it should be.

 

[Ignacio]

The Gen 2 is rated at 590 watts according to this where the Gen 1 is 490 watts.

Warchild deduced/estimated/guessed/divined there was about 120-130 spare watts available in the Gen 1...and if you take that one step further it would be 220-130 for a Gen 2. So, that's far less than the 340 spare watts you were hoping for.

Your observations though that you're seeing 13.2 with PHIDs and electric jacket seems low though--more similar to my Gen 1 profile. I can fire HIDS and electrics and keep it in the 13.4 range. I don't remember the curve, but my memory is that output goes up with RPM with 3500 cruising seeing more than 2000x. You might validate by taking that out for a higher rev cruise and see if the voltage creeps back up to somewhere like 13.9 or so.

BMW's do trump the FJR in being able to power a small town after basics...no argument. But it's one of the few weak links in the platform....less weak if you are fortunate enough to have a Gen 2.

 

[SkooterG]

FYI, here is ionbeam's previous 'most excellent' post on datel readings:

The FJR stator generates a high voltage AC output which reaches peak current from 5k rpm and up. The Rectifier/Regulator (R/R) converts the AC into DC at a voltage in excess of 14.5 volts. The regulator dumps all the excess power to ground, leaving ~14.5 volts DC on the output terminals of the regulator. The power that gets dumped to ground makes the R/R always run very hot. The Gen I stator & R/R system is rated to produce 35 amps at 14.0 volts at 5k rpm = 490 watts. Anything less than 5k rpm will produce less than 35 amps. A fixed power load that is acceptable at 5k rpm may overwhelm the charging system at 1k rpm (idle) because the stator's current output will be very low.
The battery would like to have a minimum of 13.2 volts to maintain a light trickle charge. Ideally, you would like to see the voltage at the battery terminals running 13.7 to 14.5 volts. In this sweet spot the stator is supplying sufficient current to maintain battery charge and sufficient power to run the electrical devices on the motorcycle without incurring an overheating condition.

When you see 12.8 volts at the battery terminals it indicates that the motorcycle's charging system has reached the end of its capability to supply sufficient current, and the battery is on the verge of supplying 'make-up' power. By 12.4 volts the charging circuit can no longer supply sufficient current, and the battery is starting to supply 'make-up' current and the battery is now slowly being discharged. The more significant event is that the stator is actually over-loaded and getting very hot, entering a zone where it can become permanently damaged.

With a good charging system, and a healthy, properly charged battery I would offer these guidelines for sustained voltages:

≤12.8 volts at the battery terminals – the charging system is over taxed, the battery is being discharged, and the stator is in danger of being permanently damaged.

12.8 to 13.2 volts – entering the danger zone, the battery is no longer being trickle charged and the stator is being taxed to the limits.

13.2 – 13.7 volts – undesirable but sustainable, the stator is taxed but the battery is being charged.

13.7 to 14.5 volts – schweet

12.7-12.8 volts – good battery voltage when it is fully charged and disconnected from the motorcycle; measured at 70°F

 

[Constant Mesh]

An AE consumes more power than an A. I don't know how much more. They have the same charging system so the AE will have less available accessory power.

 

[Ignacio]

An AE consumes more power than an A. I don't know how much more. They have the same charging system so the AE will have less available accessory power.

Crap! I totally missed that. For some reason I thought he got an A.

Seeing as how the AE was introduced the same year as the 100 watt bump for the platform...so it's very plausible that a good chunk of that wattage was for the AE gear....benefitting the regular A owners in the process. Joel, I would retract my previous observation and unless AE owers have additional input...consider your measurements not that strange. You might be better served to use the Gen 1 value of 120-130 watts.

 

[Joel Rappoport]

I do have an "A".

Good thought though.

 

[Ignacio]

I do have an "A".
Good thought though.

OK....you might want to change it in your profile. You chose AE in there and it's displaying to the forum that way.

 

[charismaticmegafauna]

During normal running I'm seeing 14.1 volts at anything over 2000 rpm. OK so far. My reference for this is that I rode a BMW R60/6 for 34 years, the last ten with an aftermarket 450 watt alternator.

Any help would be appreciated.

I think you'll need to reference RPM along with voltage readings? IOW: 13.X V. @ X,XXX RPM.

The FJR's system (permanent magnet powered) is dependent upon to how fast (how many times) the magnets pass by the stator coils -- more frequent = more power. I think? the 'magic number' is somewhere around 4,500 ~ 5,000 RPM for full alternator output (you may need to run in lower gears for the highway speed you're travelling?)?

And, your old Beemer had a different system -- electrically excited fields made power with less spinning (although, the old Beemer was probably geared considerably lower, too?).

Try referencing voltage with RPM..., see if that helps shed some light on the issue. :blink:

 

[SkooterG]

I think you'll need to reference RPM along with voltage readings? IOW: 13.X V. @ X,XXX RPM.The FJR's system (permanent magnet powered) is dependent upon to how fast (how many times) the magnets pass by the stator coils -- more frequent = more power. I think? the 'magic number' is somewhere around 4,500 ~ 5,000 RPM for full alternator output (you may need to run in lower gears for the highway speed you're travelling?)?

5500 rpm is the magic number.

However, in all my travels, I haven't noticed much of a difference in datel readings with all kinds of farkles going once above 2,500-3000rpm. Yeah, sure, at idle you ain't getting full pop, but once the revs climb a little bit, you're getting most of the juice.

 

[charismaticmegafauna]

However, in all my travels, I haven't noticed much of a difference in datel readings with all kinds of farkles going once above 2,500-3000rpm. Yeah, sure, at idle you ain't getting full pop, but once the revs climb a little bit, you're getting most of the juice.

Yep, you're right -- according to this chart:

There's only 7 amps available (stock) from idle to max and 15 amps (high-output).

That's about an extra 100Watts (@ 5500). The OP is adding 135 Watts -- so, it appears a deficit will result? And, a real deficit @ 2,500 RPM where ther's only about 50 Watts more.

I guess it does all come down to adding-up all the power consumers -- and (like you said) watching your voltmeter?

 

[HaulinAshe]

In colder temps, it's common for my voltmeter on the Escort 8500 (which is suprisingly accurate BTW) to display 13.2 to 13.7 volts while running heated gear. The only way to know for sure is to take an amperage reading at the battery. But IMO the batteries we use exhibit a slightly lower "mean voltage" when they are cold.

 

[SkooterG]

In colder temps, it's common for my voltmeter on the Escort 8500 (which is suprisingly accurate BTW) to display 13.2 to 13.7 volts while running heated gear. The only way to know for sure is to take an amperage reading at the battery. But IMO the batteries we use exhibit a slightly lower "mean voltage" when they are cold.

Interesting. The voltmeter on my 8500 seems to read quite high - as in about .4V-.5V higher than my datel. Also, when engine is cold, my datel reads .1V higher than when it warms up. Stator putting out reduced wattage when warm?

 

[lnewlf]

I can't read my Escort X50 because the reading hunts around like wild-possibly because I hard wired it off the accesory outlet..? Gave up on that and got a Datel..which reads about 13.4 with neck to toe Gerbings on high.