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Avc8130
| | Posted on Tuesday, September 08, 2009 - 08:22 am: | 
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Zac/CC,
Here is what I know:
From experience, on multiple occasions, I have witnessed jumping a motorcycle from a RUNNING car destroy the regulator/rectifier of a motorcycle.
Current is DRAWN, not pushed. Just because a car CAN produce more current, does not mean the bike will draw it.
Voltage, on the other hand, will be seen across an entire system as equal.
What is the charging voltage per the service manual of an 1125R? If it is lower than the car you are jumping off of, you are certainly not immune to problems.
ac |
Zac4mac
| | Posted on Tuesday, September 08, 2009 - 08:28 am: |
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Tony
Neil and I have a combined experience with this stuff approaching 60 years.
Take it as you will.
Zack |
Avc8130
| | Posted on Tuesday, September 08, 2009 - 08:39 am: |
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Zack,
What is the charging voltage for an 1125?
ac |
Avc8130
| | Posted on Tuesday, September 08, 2009 - 08:42 am: |
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FYI, a quick internet search has shown many references (unknown credentials) that support my experience of frying reg/rects.
I just want everyone to be aware of the POSSIBILITY.
Just out of curiousity, what would the advantage of the car/truck running be?
ac |
Zac4mac
| | Posted on Tuesday, September 08, 2009 - 09:52 am: |
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none really.
The bike will not pull enough energy out of the car/truck's battery to make any difference.
A slight benefit of having the slightly higher voltage to charge faster.
When jumping a battery, first you want to get some energy back into the battery so it can sustain the system.
This also places less load on a suspect or dead charging system.
Then you have to supply the energy to run the starter motor.
This is not a trivial amount of energy.
The car's battery will supply plenty of current, but the voltage will be 12.8-13.6 for a healthy system.
With the motor running, the car will supply it's charging voltage of 14.8-15.2.
As I said, the greater the potential difference - volts- the faster the energy moves - Amps.
I don't discount the possibility of damage from jumping, but, again, damage comes from spikes in voltage, mostly when making the connections.
Charging voltage on my 1125, from many tests I did a year and a half ago(we had charging issues in the very beginning with some bikes) were 14.4-14.8 V IIRC.
If in doubt as to your systems capability, take it to your dealer for testing/diagnosis/repair.
Zack |
Ccryder
| | Posted on Tuesday, September 08, 2009 - 11:06 am: |
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Z:
+1  |
Avc8130
| | Posted on Tuesday, September 08, 2009 - 11:24 am: |
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IF the car is running, any charging voltage outside the design realm for the motorcycle could cause damage to the motorcycle's electrical system.
Maybe the 1125 is designed to support higher voltages than many of the Japanese bikes, but it is pretty common on the net to read about people who have fried reg/rect jumping off running cars.
If the service manual or electrical diagnostics manual has charging voltage for the 1125 above the charging voltage of the car being jumped off there should be no issues. Can't argue that. You really can't be sure unless you have the charging specs for both vehicles. To give blanket advice could cost someone a $100+ regulator/rectifier.
YMMV
ac
(Message edited by avc8130 on September 08, 2009) |
Ccryder
| | Posted on Tuesday, September 08, 2009 - 12:16 pm: |
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ac:
We all agree if you have to jump start your m/c off a car do not have it running. That is the safest way to jump start it off a car/ truck. |
Zac4mac
| | Posted on Tuesday, September 08, 2009 - 12:19 pm: |
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Whatever Tony.
A name on a box does not change the laws of physics, nor does all the anecdotal drivel in the world.
I'll say it again, a 12 volt system is a 12 volt system.
If you didn't mind the weight, you could put the battery from a 1 ton dually in your 1125.
It would work fine, although physical fitment would be an issue.
By the same token, you could graft the charging system from a Dodge Viper into your 1125 and it also would function just fine.
I'm gonna say this one... more...time.
If in doubt as to your systems capability, take it to your dealer for testing/diagnosis/repair.
Zack |
Avc8130
| | Posted on Tuesday, September 08, 2009 - 01:22 pm: |
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Zack,
I am not trying to be a pain, I am just trying to prevent people reading this thread from possibly killing their regulator/rectifiers from not having 100% grasp on what they are doing.
I agree they are both "12volt systems", however, there are tolerances on that. Charging voltages can range from 13.2 to over 15 on spikes on some systems. It is in the tolerance stack that the issues may arise.
It's not the current from the auto that's the problem, it's the voltage.
And it's not even that the voltage is detrimental to the main electrical system of the bike (even the ECM or igniter) - it's the R/R that suffers the consequences.
The output voltage from the running car's alternator may be higher than the bike's R/R typical threshold, which means that in an effort to try to contol the output, the bike's R/R will shunt 100% of it's generated current from its stator once the engine starts.
When the R/R is shunting the extra voltage it will create heat. If you leave the system at elevated charge levels it could overheat the R/R and kill it. If you jump start and immediately pull the running car supply, it might be ok.
But why would it ever be necessary to have the auto running? The current required to start a bike will be more than adequately supplied by a car battery. There is no requirement and minimal advantage in having the car running from a purely system voltage perspective - if it won't start off a cage battery unassisted by it's alternator, then it's not going to start off a fully-charged bike battery either, so you have other problems to worry about!
I just didn't want to see anyone out there try jumping a bike off a running car and come back claiming it fried their R/R. Maybe the 1125r R/R voltage threshold is high enough, maybe it isn't. I just don't know.
I know you work at a dealer, do you have access to the technical specifications for the R/R used on Buells (I imagine it is common across the brand, as most other components seem to be)?
ac |
Ccryder
| | Posted on Tuesday, September 08, 2009 - 04:28 pm: |
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ac:
Point made. |
Zac4mac
| | Posted on Tuesday, September 08, 2009 - 10:42 pm: |
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Tony - I understand your concern.
If you really want to be safe in a "jump" condition, hook up with both vehicles off.
Let sit for a half hour or so, then disconnect and try to start.
Remember this is for emergencies and your stator/regulator may already be fried.
That's why I discount a lot of the stories.
Personally, I have jumped Loretta several times early on when I flooded her(my stupidity).
Only later did I find out about the "flood recovery mode" built in.
Still running the original battery, stator and regulator.
As far as heat, the R/R on the 11 is on a huge heatsink, a point I made to one looking to relocate the regulator.
I have not done any failure analysis on regulators, so I can't say for sure BUT-
Most solid state failures I HAVE seen were due to voltage spikes generated during connect/disconnect situations.
Best scenario - get your system up to snuff and keep it there.
Prevention is better than repair.
Z |
Avc8130
| | Posted on Tuesday, September 08, 2009 - 10:48 pm: |
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Zack,
What is the built in "flood recovery mode"?
FWIW, my baby sleeps on an umbilical cord. My track bike still has its original 2002 battery. I have 6 battery tenders in the garage!
ac |
Chadhargis
| | Posted on Tuesday, September 08, 2009 - 11:08 pm: |
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Battery Tenders WORK!
I've only replaced one battery in my riding career, and that was when I thought the one in my Ulysses was bad, when in fact, it was the VR/stator that went out.
All my bikes are plugged in when not in use. Even my scooter.  |
R2s
| | Posted on Wednesday, September 09, 2009 - 01:58 am: |
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O.k. guys, Its not the voltage, its the current. Also a dead battery acts like a short( depending on how dead it is). The whole charging system is exposed to this current when it is just sitting. If the battery is only partially drained (it could only be a partial drain and it will not be sufficient to crank) It might not act like a total short and you might get away with it. Or just disconnect the battery from the bike.
Its the initial inrush or current that can be the problem. As the battery charges this resistance goes up and the current draw decreases. The car running or not is not gonna matter. Although the slightly higher voltage and the continuous charging helps in normal jump starting. The car battery actually has potential to put out more amps than the cars alternator. 150-200 cranking amps can be generated and transferred into your 1125's charging system in a worst case scenario ( battery totally dead acting like a dead short). this of course would depend on the motorcycle batteries internal resistance, which would be fairly low when dead. You see the sparks when you hook up the dead battery to be jumped. You remember MacGyver welding with a car battery and a nickel.
But seriously, that is why they sell the low amperage type of chargers for motorcycles. They have a limited amount of current available to charge the battery.
I may not be a motorcycle mechanic,I once was an auto mechanic and I work with related technologies and I am an expert in my field. I know what I am talking about. |
R2s
| | Posted on Wednesday, September 09, 2009 - 07:32 pm: |
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Yeah, I know, I exaggerated a little to make a point, and sometimes a dead cell won't conduct at all until it builds up a bit of a charge then the inrush current will ramp up. And the inrush current is more likely to spike up to 20-30 amps, but that is still more then you would like you motorcycles electrical system to see. |
Zac4mac
| | Posted on Thursday, September 10, 2009 - 11:23 am: |
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Flood recovery -
key off, throttle WFO, key on for 4 seconds, turn off key, let go throttle.
repeat once.
Key on, wait 10 seconds, push start button, DON'T touch throttle until running. |
Fast1075
| | Posted on Thursday, September 10, 2009 - 12:45 pm: |
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All 12 volt systems run at more or less the same output voltage...one thing that most often kills charging systems is the fact that the battery is dead...the 1125 charging system is a fixed field system, alternator output is determined strictly by rpm...the regulator works by shunting excess VOLTAGE through a resistor to ground...
A dead battery (lacking load) will allow the alternator to run at max output and over heat the windings..(or damage the windings by induced harmonic hum)...it is always (except in a dire emergency) best to recharge the dead battery before running the motor...then the system can do what it is designed to do...provide the required output to operate the various loads and recharge the battery from which current was consumed to crank the engine. |
Reepicheep
| | Posted on Thursday, September 10, 2009 - 02:03 pm: |
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Your first paragraph was perfect fast, but your second half had parts backwards.
A dead battery is when your VR is happiest. Like you say, it's a shut regulator, so if the battery is charging, most of the power the system produces is going into the battery.
When the battery is charged, that power gets dissipated by the stator and voltage regulator. That's actually when the stator and VR is working the hardest.
Now a "bad" battery, that won't take any charge, is also really bad for the stator and VR. We are again back in a state where the stator and VR have to dissipate all the power (power=heat).
You can do the math to verify... power is volts times amps. The stator is in series with the battery, the VR is in parallel with the stator. If the shunt regulator is really a shunt regulator (and to the best of our knowledge it is), the stator always does the same work... the VR just decides what it has to eat and what it can force feed the battery.
(Actually, because a battery "shorts" out the stator to 12 volts, but the VR "shorts" out the stator to .6 volts, I suspect the stator probably works the hardest on a fully charged battery... though I doubt it's much of a difference)
Some of the good information in this thread does have me rethinking something though... if your jumping car has a higher voltage then the regulator wants to regulate to, then the car will be going all out to try and maintain it's voltage, but your bike VR will be going all out to try and shunt that down to what it wants to regulate.
So it *is* a good idea to jump your bike only from cars that aren't running. Battery voltage (because of chemistry) will always be beneath the VR regulating voltage, that should always be safe. But charging / running voltage might not be... |
Fast1075
| | Posted on Thursday, September 10, 2009 - 02:18 pm: |
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It's a shunt regulator...if the charging system was an "excited field" type, the regulator serves to vary the input to the field coil, thus regulating output...more accurately the strenght of the magnetic field in the rotor is regulated...thus maintaining the voltage as the load varies.
I am not a real fan of fixed field systems..the best, most reliable motorcycle charging systems were the old Honda I-4's...the "brushless" alternators had very good output and NO wearing parts...the regulator was a simple single point magnetic type...and had a stand alone selenium rectifier...very simple, very effective. |
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