Posted by LJ on May 7, 2007, 11:28 pm
> On 7 May 2007 13:56:39 -0700, dzaremba@gmail.com wrote:
>>If so, is the procedure any different than that for jump starting a
>>dead car battery?
> Your voltage regulation gear on the bike is sized to take care of the
> excess electrons created by it's on-board charging system. If you use a
> larger vehicle to jump it like a car, do NOT start the vehicle. Now your
> VR
> has to sink all those many more electrons produced by the larger charging
> system on the car. If you just use the battery, you should be fine as
> should your VR since the battery isn't at a voltage that's high enough to
> cause regulation. Good luck.
> Mike
> --
> Mike W.
> 96 XR400
> 99 KZ1000P
> 70 CT70
> 71 KG 100 (Hodaka-powered)
Your best bet is to buy the correct trickle charger for your Beemer. If you
ever let it sit for more than a few weeks at a time youll need one anyhow.
You can buy the BMW licensed charger or the equivilent Deltran. The newer
beemers with gel batteries require a different charger than the older
beemers. These come with a connector that allows you to recharge your
battery via the accessory connector which is much easier than trying to
access your battery.
You can jump your bike from a car, but as others have mentioned, make sure
the car is turned off as you could end up screwing up the donor;s charge
system
Posted by Albrecht via MotorcycleKB.com on May 8, 2007, 1:26 pm
Mike W. wrote:
>Your voltage regulation gear on the bike is sized to take care of the
>excess electrons created by it's on-board charging system.
That's true.
>If you use a
>larger vehicle to jump it like a car, do NOT start the vehicle. Now your VR
>has to sink all those many more electrons produced by the larger charging
>system on the car.
This idea is so fantastic it demands a response.
The motorcycle's voltage regulator circuit senses a rise in DC voltage at the
battery positive terminal, or it senses a rise in AC voltage between a pair
of power diodes inside the regulator where one phase of the stator is
connected.
Whether it's AC or DC voltage which is sensed, it will be something between
14.5 to 15.5 volts that triggers the shunt type voltage regulator to do its
thing.
The sensing circuit consists of a resistor bridge consisting of a 100 ohm
resistor and a 1000 ohm resistor and a zener diode which is triggered by the
AC or DC voltage voltage rise.
The zener diode triggers a silicon control rectifier to ground out one phase
of the *motorcycle*s* three phase stator. This reduces the stator's power
ouput by half, but only for half a cycle, since the three phase stator must
use each leg, in rotation, to complete the circuit.
There is *no way in hell* a shunt type voltage regulator of the type commonly
seen on motorcycles could ever shunt any appreciable amount of the car's
electrical power to ground.
IOW, the motorcycle voltage regulator will always regulate the motorcycle
alternator's AC voltage, and will never regulate the car's *battery* voltage.
Now, if the voltage regulator was just a huge zener diode as seen on old
Triumphs around 1970....
Who wants to p*iss off this bridge next?
--
Message posted via MotorcycleKB.com
http://www.motorcyclekb.com/Uwe/Forums.aspx/tech/200705/1
Posted by oldgeezer on May 8, 2007, 7:12 pm
Albrecht via MotorcycleKB.com schreef:
<some snipping here and there>
> The motorcycle's voltage regulator circuit senses a rise in DC voltage at the
> battery positive terminal, or it senses a rise in AC voltage between a pair
> of power diodes inside the regulator where one phase of the stator is
> connected.
> Whether it's AC or DC voltage which is sensed, it will be something between
> 14.5 to 15.5 volts that triggers the shunt type voltage regulator to do its
> thing.
So far, so good.
> The sensing circuit consists of a resistor bridge consisting of a 100 ohm
> resistor and a 1000 ohm resistor and a zener diode which is triggered by the
> AC or DC voltage voltage rise.
What makes you think that *all* RRs have a 100 Ohm/1000 Ohm inside?
> The zener diode triggers a silicon control rectifier to ground out one phase
> of the *motorcycle*s* three phase stator. This reduces the stator's power
> ouput by half, but only for half a cycle, since the three phase stator must
> use each leg, in rotation, to complete the circuit.
Here you go a bit astray. One phase shunting was done in the
seventies.
The 'silicon control rectifier' is named Thyristor.
Zener diodes are used reverse mounted (blocking) and start conducting
in the 'wrong way' when the voltage across them reaches the specific
threshold they are designed for..
Thyristors do almost the same, but start reverse conducting only
when a trigger signal is given to them (zeners have two leads,
thyristors have three leads, one being the trigger connector).
The zeners each trigger a Thyristor, and can be very small
because the trigger signal is usually in the milliAmps range.
Above you describe my electric disaster Suzi GT250 (1970).
That had a permanent magnet three phase generator of which
only a single phase was shunted, so it kept on puttting Amps
in my battery, even when the battery was full.
Only one leg 'shunted' and the other legs kept on pumping
electrons. Not so many as before, but still too much to handle
for the battery. Yes, half of the normal output. The diagram was
different and I cannot scribble that here, but effectively they
shunted 1.5 of the three windings, by changing a full
bridge rectifier into a half-bridge rectifier.
My later Kawa and Honda (around 1985) all had a three phase
permanent magnet generator, and all three phases were
shunt to ground when the voltage got above threshold.
The voltage sensor was a seperate wire, basically monitoring
the battery voltage.
It is important to realize that the center of the generator
in a star configuration (where the three coils are connected
to eachother) is NOT connected to ground. It electrically
'floats'.
It means that the 12V (and over) is generated by two coils
in series. Over and over again.
The regulator thyristors carry the full load of the generator
when the voltage gets too high, shorting two coils at a time,
(two thyristors in series, both conducting) no matter if the
Voltage is positive or negative.
Thyristors work like switches. When 'open' they behave
as diode (current one way only) but when 'closed' they
behave as a contact, and current can flow in both directions.
When closed, then no output from the generator
(momentarily) until the trigger signal (too high a
voltage) is withdrawn AND the current 'goes through zero'.
The latter is when the voltage reverses, which will happen
at an AC generator.
Was the generator a DC thing (battery) then even
when the trigger signal was withdrawn the thyristor
would continue conducting until the battery is flat.
> There is *no way in hell* a shunt type voltage regulator of the type commonly
> seen on motorcycles could ever shunt any appreciable amount of the car's
> electrical power to ground.
This is too much generalizing. There could be motorcycle
RR's that can you can mount in a car without a problem.
Returning to the original situation: jump starting with
a car.
The RR (motorcycle) wont shunt the car because the
thyristors are connected to the car via the reverse(!)
rectifier diodes that block current towards the motorcycle
regulator.
> IOW, the motorcycle voltage regulator will always regulate the motorcycle
> alternator's AC voltage, and will never regulate the car's *battery* voltage.
I think that is exactly what I said above.
> Now, if the voltage regulator was just a huge zener diode as seen on old
> Triumphs around 1970....
> Who wants to p*iss off this bridge next?
Most of what you wrote is correct. Are you p*issed off now?
Rob.
Posted by rabyrnesjr@gmail.com on May 9, 2007, 5:47 am
On May 7, 4:56 pm, dzare...@gmail.com wrote:
> I left the parking lights on last night on my BMW R1150RT and now
> there's not enough juice left to start the bike.
> Is it safe to jump start my motorcycle battery from the battery on my
> pickup truck?
> If so, is the procedure any different than that for jump starting a
> dead car battery?
> Don
This is my experience in a related issue. I had trouble with an AGM
battery (MK brand) refusing to hold a charge over a (0 deg F) cold
night.
In my case, the bike in question is a 2004 Kawasaki Vulcan 1600
cruiser. I did successfully jump-start off my Chevy K1500 @ truck
engine running, and judging by the sluggish rotation rate of the bike
starter I would say that I was DEFINITELY not over-juicing the bike
and its battery. This was in spite of an AWG #4 jumper cable.
I had gotten the MK battery "on my own", and the failure caused
me to replace it with the OEM make, by Sumitomo. The difference:
the Sumitomo STZ16-BS is "flooded technology", meaning classic
liquid electrolyte and not gel or AGM (absorptive glass matting).
I reckon that thermal contraction could have ripped some of the
AGM off the sponge anode in the MK, but obviously this cannot
happen with liquid electrolyte. Incidentally, the Sumitomo battery
has hydrogen storage bladders, etc, so that it truly functions as
"maintenance free".
Hope that helps!
Raymond A. Byrnes, Jr.
B.S.E.E., M.S., Ph.D.
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>>If so, is the procedure any different than that for jump starting a
>>dead car battery?
> Your voltage regulation gear on the bike is sized to take care of the
> excess electrons created by it's on-board charging system. If you use a
> larger vehicle to jump it like a car, do NOT start the vehicle. Now your
> VR
> has to sink all those many more electrons produced by the larger charging
> system on the car. If you just use the battery, you should be fine as
> should your VR since the battery isn't at a voltage that's high enough to
> cause regulation. Good luck.
> Mike
> --
> Mike W.
> 96 XR400
> 99 KZ1000P
> 70 CT70
> 71 KG 100 (Hodaka-powered)