On the road - inconsistent voltage, help diagnosing please!

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by jconly, Aug 8, 2012.

  1. Hodgo

    Hodgo TWIN Cylinder ADV

    Joined:
    Jul 2, 2009
    Oddometer:
    1,653
    Location:
    Brisbane
    Spent some time reading this thread and am inclined to think that the VR is shot.

    Symptoms of course only show up when it gets hot. VR's are what's called shunt regulators... ie when the battery is charged they shunt the current to ground which causes heat.

    If the voltages are all over the place that suggests fouled connectors. The AC your seeing sounds within spec.

    With the ADV bikes the regulator is in a place that is very susceptible to water ingress, as well as the battery. If the battery has connectors similar to a motobat battery make sure that the posts are on tight and that the earth strap has been removed and cleaned.

    One would also think that and 8ah battery would be way too small for a 990.

    The 12ah battery on my SE will run UHF radio, Heated Grips, two Lightforce Lights & Two fans with very little voltage drop.
    #21
  2. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Thanks, have checked those out, and basically every other Shindengen writeup I could find.

    I'm on it! So here's a little update...


    Finally made it back home to NYC... what a trip it's been.
    A day or two before leaving, I decided to throw the original battery in. Then I decided to test it out again, and by test it... I mean do something stupid like go ride some more technical trails in the woods. Mistake.

    A few drops, and a few slow sections and the bike wouldn't start up. Battery completely dead. And it went from a good healthy reading of running around 13.5V and a resting voltage of 12.8V, to completely nothing. No lights w/ key on, nothing. Of course I didn't bring my new spare with me. So, I pushed the sucker as far up a hill out of the woods as I could before surrendering and calling a local friend. He picked me up and took me back to my temporary garage to get the new battery. Put it in and all was fine.

    When I got the old 8AH battery home after the ride, it was reading a resting voltage of around 12.7V. This was about 2 hours after it wouldn't even light up the bike. :huh I let it sit the rest of the night, and checked again in the morning. It had climbed to 12.9V. At this point, I'm pretty convinced that it's just plain faulty. Load tested fine at the store, but yea, totally unreliable.

    So, of course I do the sensible thing and throw it back in the bike for my home! Hey why fry a brand new batt if I don't have to.

    So, I figure the ride back to NYC, I'll just take all interstate. Keep the charging system running at it's 13.4V, keep the fan off and all will be good. BORING! Hopped off, rode some twisty dirt roads. Kept the fan off, but after hopping back onto some local tarmac, I watched the volts just drop, without the fan running. And by drop I mean not just down to the 12.7V on the battery, I mean down to 12... 11.8V etc.

    Of course, next fuel stop the bike wont start, so I throw in the new battery. Fingers crossed because at this point it looks like the VR had just completely shit the bed. New battery in and everything is running fine (consistent with the symptoms.) Thank god. Managed to make it back to my garage. Plugged the new battery in the tender and before leaving the garage that night it was reading full charge.


    So, I ordered up a Shindengen FH020AA. I had read some reports of people using the FH012AA. Wanted to make sure there wasn't a difference, so for anyone wondering the 020 replaces the 012. So, seems that's the one to go with. Expecting it to show up tomorrow or Thur, so stay posted.
    #22
  3. mousitsas

    mousitsas Long timer

    Joined:
    Oct 10, 2008
    Oddometer:
    3,308
    Location:
    Athens, Greece
    When that happened to me, the battery was on its way to cross to the other side. Put a fresh battery in and voltage went steady again.
    #23
  4. Dustodust

    Dustodust Long timer

    Joined:
    Oct 9, 2009
    Oddometer:
    1,422
    Location:
    Hillsboro Oregon
    I was gonna say......
    voltage regulator and stator rarely if ever malfunction
    usually it is bad battery connections or a weakened battery
    leaving a battery low on charge overnight will kill it
    and it needs to be fresh and not sitting on the shelf at the shop for 10 years and not overcharged intitially
    you can even get a new battery that is junk too, rarly but it happens
    8 AH is no where near enough, starting it would be like trying to plow a field with a pony, 14 AH is more like a plow horse

    battery voltage should be more like 13 to 13.8 at rest
    12-13volts could be a sign that it is getting weak on storage amps
    sounds like the VR is working properly by dropping back at hi rev
    all the readings you report point to battery condition
    the battery is the capacitor in the charging system , If the battery has a weak cell, voltage fluctuations will be apparent as the voltage regulator attempts to compensate for the lack of steady rate capacitance through the battery

    Battery is difficult to test for amperage capacity .sometimes voltage looks OK and the lights seem brite, but it just doesnt have enough output power, You would need a load tester,
    it sucks because it is hard to believe the battery is actually bad and it costs so much to gamble on at $150 for a battery so I dont want to be the guy to tell you to roll the dice
    I got a nice Yuasa here in the shed that has been holding 12.2 volts for years but it wont start the bike , I keep it around to test 12 volt devices and such

    always buy the highest quality lead acid battery possible for this bike and treat her like a lady, its worth the extra $
    #24
  5. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Wish is just was the battery, but even with the new one in for the remainder of the trip, when that fan hit, down to 12.8 and lower it went.
    #25
  6. Sumi

    Sumi Long timer

    Joined:
    Mar 30, 2010
    Oddometer:
    1,897
    Location:
    Hungary
    Using my GPSMAP 276c as a voltmeter would give me strange voltages as well..
    Anything from 11.9V-14V.. (fluctuating between 12.9-13.4 is the most common readout on my unit while cruising at let's say.. 4500 rpm)

    I've been using the bike like this for almost a year now, and there is not a problem with it..

    I guess it's only the GPS's voltmeter, that's not that accurate ( I guess it under-measures the correct voltage by a 0.5V minimum).

    I wouldn't be scared if the volts stay between ~12.0-~14.5V (when engine is running at any rpm)

    just my $0.02:)
    #26
  7. bomose

    bomose Long timer

    Joined:
    Jul 22, 2007
    Oddometer:
    1,936
    Location:
    Dixie
    Mine seems to be working OK right now. I went for a 250 mile ride Sunday with no problems. I've started the bike 6 times in a row. The resting rate is @ 12.9 volts. At 5000 rpm it charges @ 14.1. I'm leaving Thursday morning. Wish me luck. I did hook up a wire so I could jump start it if I had to. Problem is, I'll be riding with a Harley guy, so that would be embarrassing.:eek1 I'll report back in 10 days, if I'm able.
    #27
  8. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Good luck!
    12.9 resting does seem low to me (I guess it depends what kind of load you have at idle) but at least your having, what seems to me at least, a normal increase in V w/ RPM.

    My idea of how a charging system "should" work may be incorrect, but it is my ultimate goal... That is a resting rate of at least 14.0 V under a "normal" load, and a rate of around 14.3V under throttle. We'll see how this Shindengen effects things, but I'm hoping that's the outcome.

    Especially as I plan to add a greater load to the system compared to the minimal voltmeter + gps combo I'm running now. Ultimate goal is to add heated grips (3A) and at least one 2A USB charging load to the system with no adverse effects. Ideally a charging solution for laptop as well. Shouldn't be a problem with a properly functioning RR IMHO.
    #28
  9. GZERO

    GZERO Fixing stuff around

    Joined:
    Aug 8, 2011
    Oddometer:
    266
    Location:
    Panama, but originally from Venezuela
    Let me know how this works.
    #29
  10. gefr

    gefr Life is a trip

    Joined:
    Nov 26, 2005
    Oddometer:
    4,614
    Location:
    East Med, Greece
    During a trip, the lights could be on, the fan start working, lights turned on or heated equipment. People that see voltage fluctuations have all consumption equipment unchanged?
    Cheers.
    #30
  11. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Yes, during all of these readings, there is always the same load on the bike... with the obvious variable of the fan.
    #31
  12. GZERO

    GZERO Fixing stuff around

    Joined:
    Aug 8, 2011
    Oddometer:
    266
    Location:
    Panama, but originally from Venezuela
    from the top of my head, i tested a 990 that had the ridgid led lights, and with the bike at idle and led lights the voltage was around 14 volts, but when the fan kicked in it went down to 12.6 volts, mind you this battery wasn't that good at around 12.5 static.
    #32
  13. SS in Vzla.

    SS in Vzla. Totally Normal? I'm not!

    Joined:
    Dec 31, 2006
    Oddometer:
    1,230
    Location:
    Sugar Land, TX
    I seem to have the same behavior from my voltage on the 276C. I've tested with a "proper" voltmeter and the variations of voltage where still present but not that large. The bike works with no problems, so maybe it is normal?
    #33
  14. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Ok so, a little update.

    I installed the Shindengen the other day. Sorry no pictures, should have done a write up but was in a hurry,

    It's a simple install though, especially with the right crimp tool. I bought mine a while back from VintageConnections.com. Got the Shindengen from roadster cycles, as recommended above. It bolts right up, perfect fit.

    Pulled the old connector from the stator off, and crimped the wires directly to the connector for the VR. One less connection is always good, so I also took the VR + & - right to the battery.

    This left the old connector on the harness for the VR + open. I've read some reports of people taping over it, but I wasn't happy with this.

    It's a very simple style connector, the terminals inside are just non-latching blade style male and female. Just depress the tangs inside and they slide right out.. So that's what I did. Pulled the connector off the harness side, and replaced the old ones with new, less corroded terminals (not that it was that bad before). Pulled the connector off the original VR side, took a piece of wire and crimes new terminals on each end, and stuck em in. I then packed the connector with di-electric and pushed it all together, effectively connecting the two + wires harness side and closing the circuit.

    So, did it work? Kinda.


    My voltage has risen across the board, so this is good.

    14.2 - 14.3 V resting and cool.
    14.1 with the fan on.
    Looks perfect in the garage.

    But on the road, different story.
    14.3 under throttle. Good.
    14.2 - 14.3 idling. Good.
    Fan on, 14.1 idling, even while HOT. Good.

    But if I pull that brake lever, while relatively cool, about a .2 V drop. While hot, a full .5 V. Seems high. I'm going to go pull my ABS fuse now and see how it acts. I figure it's got to be the ABS system and not the LED brake light. The 55W high beam only drops the system .1V

    Anybody else experiencing a drop from ABS like this? I definitively have a little air in my line, I wonder if this could be a culprit as well?
    #34
  15. GZERO

    GZERO Fixing stuff around

    Joined:
    Aug 8, 2011
    Oddometer:
    266
    Location:
    Panama, but originally from Venezuela
    It seems pretty good, those numbers are very good.
    Remember that the stock stator doesn't put that much out (450 watts).
    I would leave it as it is, make sure the batery is charged and that's it.
    #35
  16. GoNOW

    GoNOW Long timer

    Joined:
    Feb 22, 2006
    Oddometer:
    1,604
    My 276C does the same thing. To the point it will warn me about it switching over to it's own battery power because the bike voltage is too low. But it's only for a second or two.
    #36
  17. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Well, interestingly, pulling the ABS fuse didn't lead to any conclusive results.
    At first, it helped. I didn't have the .5V drops. Then, they started to appear, seemingly randomly.

    I haven't had the bike in the garage to check voltage with the multimeter in a few days (trying to use the damn thing as a commuter) but letting it sit outside has definitely resulted in a weakening battery. Went from a quick turn over, to a bit of a struggle in two days.

    I feel a lot of it can be the city riding I do around here.
    It's one thing when I'm on a road trip and the bike is running for hours at a time, but NYC is a little different. Lots of stop and go, and that fan is ALWAYS on. It doesn't really give the battery much of a chance to charge I suppose.

    And I'd let it go if it weren't for this, but I am chasing the best performance possible. Getting stranded in the city is EXPENSIVE.

    I'll admit though, maybe I a digging too far into this, but part of this quest is to learn more about my electrical system and the finer details to be prepared for having the bike permanently on the road coming this winter. (Planning to ride, throw it in storage, fly home for work, fly back, keep going etc.) I feel I'm going to need to add a second fan for this, since I'm heading south, and I want to make sure it's going to work fine. It comes scary close to overheating in the city here during the summer! Already has on me on a few occasions.

    I'll be headed to the garage tomorrow morning to check the batteries resting voltage.

    In the meantime, I wanted to figure out what the actual load is on the bike under normal conditions.
    Here's what I calculated, all at 12V of course:


    License Plate Light - 0.8333A - 10W
    Brake Light - 1.75A - 21W
    Running Lights - 0.4167A - 5W
    Headlight (Low) - 4.5833A - 55W
    Fan (Max A rating) - 4A - 48W
    GPS (Assumed) - 2A - 24W

    So, we're looking at somewhere around 163W of usage.
    Not including the load of the ECU, ABS system, and what else is there? Dash lights..

    The stator is rated @ 450W, 27.5A @ 12V. But that's at 6000 RPM.
    I'll test to see what it puts out W wise at 1500 RPM.

    I suppose the one other factor I really need to learn about is resistance though, and how that factors into the equation.
    #37
  18. GZERO

    GZERO Fixing stuff around

    Joined:
    Aug 8, 2011
    Oddometer:
    266
    Location:
    Panama, but originally from Venezuela
    try taking the light fuse out when riding in the city.
    but yeah, city driving in heavy traffic kills these bikes.
    You should get the second fan.
    #38
  19. gefr

    gefr Life is a trip

    Joined:
    Nov 26, 2005
    Oddometer:
    4,614
    Location:
    East Med, Greece
    The plastic radiator guard should also be removed. Too restrictive.
    Xenon lights should bing down consumption if you install 33W. Rear brake lights and running lights and front running lights could be replaced with leds. I think the front position light could be 1W and the rear position lights 1W X 2 and brake light -I couldn't find specs-.
    On the other hand your voltage readings are excellent. The only things that could get you in trouble would be weak battery, a short or fuel pump dying in very hot conditions.
    Cheers.
    #39
  20. jconly

    jconly Been here awhile

    Joined:
    Aug 18, 2009
    Oddometer:
    534
    Location:
    NYC
    Thanks for the feedback guys.
    I will say I sure am pleased with my numbers now.

    Removing the radiator fins does seem like a good solution for around the city (especially the crawling long tunnel I have to cross to enter it after a ride.. this is where it always overheats!)

    I'm off to the garage now to play.
    Going to hit the road in a few days here actually, so we'll see how it all REALLY goes.
    Anxious to see where the battery sits though. After another night of sitting.
    #40