Although you’re correct that the power comes from the alternator while the engine is running, if Jsouth increases the voltage regulator’s setpoint to 14.7V from 14.0V, the power delivered to a resistively heated jacket or pair of gloves will increase by 10% (P=V*V/R).Originally Posted by beemerphile
Just want to point out that the Pathblazer headlight modulator from Kisan Electronics has a maximum voltage in their product manual - 14.5 volts. I recently had a problem with a faulty battery in my Airhead. Part of the problem also showed as voltage spikes getting past the regulator. They showed on a digital volt meter as 14.8 - 14.9 volts. When I was done replacing the battery and voltage regulator, the installed Pathblazer modulator had failed. Kisan was great and offered a discount to me on a replacement modulator. It is possible that other electrical accessories might have problems running with high voltage or reduced lifespan.
Michael Stock, Trinity, NC
R1100RT, R100, R60/6
That means that the Kisan won’t work with motorcycles that have a regulator designed for an agm battery which is most of the r1200 bikes. IMO parts that go into vehicles should be able to withstand the voltage spike produced by disconnecting the battery cable (>>20V) on a running engine. Sadly that isn’t always the case.
+1000 Good equipment/designs allow for that.
'
Ufda happens..........
Need your R11xx Hall sensor rewired? PM me.
Roger, I would never pretend to know this stuff as well as you do, but I took his comment to mean "in order to have the power to run additional loads", and not "to run them with higher heat output". Increasing the voltage regulator setpoint will take the battery to a higher state of charge, make lights brighter and make heaters hotter - but only so long as there is sufficient alternator capacity to produce the resultant watts. If he outruns the alternator's capacity, the voltage will not build even with the voltage regulator fully "on".
Lee A. Dickinson - Danielsville, GA USA
Airheads #3480 | Iron Butt Assn. #8914
1976 R75/6 - 1992 R100RS - 1993 K1100RS - 2013 R1200GS
Lee, I went back and read that and see what you're saying. Raising the voltage won't solve the problem of overloading the alternator but will warm up the seat a bit if the alternator's not overloaded. Looking at the fuse panel, BMW was thinking about something less than 15A for "user stuff".
POWER (watts) is Voltage X Current, V X I = Watts. An extra 0.4 volts X 40 to 50 amps is 16 to 20 watts. Not a huge increase over the stock VR but a somewhat better Alternator output and somewhat better peak battery storage. I may decide the VR cost and installation effort are not justified by the small gain.
Rainwater
You have a 50 amp alternator on a 2002 RT. With the loads you are adding there should be no need for additional alternator output to drive them. However, raising the VR setpoint will result in a higher state of charge on the AGM battery and it is worth doing for that reason alone. Being cheap, on my 2004 R1150 instead of changing the built-in VR in the alternator, I cut the ground between the VR ground and the alternator ground and inserted a 1N5402 diode to fool the voltage regulator into thinking that the voltage was 1/2 volt lower than it thought it was, which brought the system voltage up by that amount.
Lee A. Dickinson - Danielsville, GA USA
Airheads #3480 | Iron Butt Assn. #8914
1976 R75/6 - 1992 R100RS - 1993 K1100RS - 2013 R1200GS
Lee, could you maybe post a picture of where and how to do that?
I sold the bike and didn't retain any photographs. If you remove the VR from the alternator, you can see where the negative lead from the VR wraps around to contact the grounded mounting post bolt. I cut that conductor and inserted the diode in the break. The cathode stripe on the diode is on the chassis ground side. You are not using the diode as a block, but are conducting through it and using the forward voltage drop of the diode to reduce the sensed voltage. This causes the VR to increase the rotor current and raise the system voltage.
EDITED TO ADD: I did Google around and find this write-up on the modification. It is not our specific hardware, but it is a Motorola VR and similar in construction...
http://www.hax.se/alternator/
Last edited by beemerphile; 10-10-2017 at 11:07 AM.
Lee A. Dickinson - Danielsville, GA USA
Airheads #3480 | Iron Butt Assn. #8914
1976 R75/6 - 1992 R100RS - 1993 K1100RS - 2013 R1200GS
Here’s how I implemented the diode mod on my ‘04RT: https://forums.bmwmoa.org/showthread...l=1#post907139.
Last edited by roger 04 rt; 10-10-2017 at 01:40 PM.
Thanks to both of you!
So there's no way to get at the regulator/brush assembly without taking the alternator out, and for that one really needs to remove all the stuff above (battery, ECU/Motronic, ABS unit)? My PC680 is now 8 years old, so I'm thinking of replacing it next spring. Maybe I'll switch back to a battery that will work with the standard regulator as is.
Last edited by Gruesome; 10-11-2017 at 05:02 PM.
Yes, it is a lot of work, but nuts and bolts really. If your PC680 lasted eight years so far, that is good service. Why do anything differently? You could let it spend some time on an AGM rated de-sulfating charger every now and then and call it a day.
Lee A. Dickinson - Danielsville, GA USA
Airheads #3480 | Iron Butt Assn. #8914
1976 R75/6 - 1992 R100RS - 1993 K1100RS - 2013 R1200GS
Exactly!
I regularly (for several years now) run into starting trouble during the riding season. I got stranded two weeks ago after half an hour of stop-and-go traffic had emptied the battery to the point that it wouldn't start anymore. I now added a volt meter (which doesn't work right, so needs replacement), and a jump start post, and bought a lithium-ion jump start battery, but I'd rather deal with the root source of this trouble.
I do recondition/charge the battery (at the proper voltage) every winter, but I have no good way of attaching a charger during the riding season (bike is parked outside).
Otherwise the bike is very reliable, and runs smoother than ever.
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