750 Bosch Voltage Regulator adjustment

Mario at thunderbikes (Guzzi )uses VW one on the older Eldorado bikes, run the same generator, Bosch 113903803e. Looks like lots of them in the US. That doesn't line up with the part numbers that Piet had, but it is Bosch solid state reg.
 
I learned from the DVR4 technician that you should use the 11 amp version on the bikes to protect dynamo, wiring and battery from excess current. The 11 amp is not its capacity but its limiter value. If you use the VW version with the much higher current limiting level you may endanger the bikes electrical components as it will not protect them from the potentially much higher current.
 
arancia said:
I learned from the DVR4 technician that you should use the 11 amp version on the bikes to protect dynamo, wiring and battery from excess current. The 11 amp is not its capacity but its limiter value. If you use the VW version with the much higher current limiting level you may endanger the bikes electrical components as it will not protect them from the potentially much higher current.
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I used the old style vibrating contact (analogue?) 22amp VW ones for a few years, they generally worked fine, no problems with generator, wiring or battery, but I did lots of touring at fairly high revs back then, and the resistor thing on the underside of them used to burn out. On the 22A VW type ones they were flimsy wire wound things whereas on the original Lav Bosch it was much more solid. Perhaps it would have been ok had I used my headlight all the time. Can't see why an electronic one would be dangerous, but as you say, all the manufacturers of the various electronic ones say to get the 11amp one.
 
I have mentioned before that last time I had my generator tested the guy said it put out 22 amps, and said that the only difference between it and the VW one was the air slots for cooling. He also was the only person ever to properly adjust my regulator which he had coupled to the genny during the testing. He was very familiar with those gennys.
Through my years with the SF, the regulator was an occasional problem, and I suspect that the huge original battery managed to cover over some of it, and now with people using as small a battery as they can get away with any weakness is accentuated.
 
This is majorly turning into a mindfuck! Generator still only puts out 11 amps? I don't know how this works. So if you are putting out 22 amps wouldn't an 11 amp regulator blow up?
 
Don't stress about it Marty. Just get an electronic reg for the 11amp system - unless you can get someone to properly set up the original one. The genny is as good as bulletproof, the only possible weakness is it needs a few revs to be putting out much current, and 11 amps is heaps (11amps x 12v = 132watts) isn't it?
 
Trying to read the dvr4 website, but if the guzzi guys are running the vw bosch one, and piet is using the bosch one, sounds like the way to go, and it is available in sydney. Looks like the dvr4 on is in the uk.
 
Ok I've done some more research, a 30 amp regulator off a VW will be fine. It just means it can handle up to 30amps, not that it will make the Genny try and push out 30 amps. Your Genny blowing up may have just been a coincidence Q.
 
arancia said:
The 11 amp is not its capacity but its limiter value.
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That makes perfect sense, but I'm not sure that the Bosch VW type VR's have a current limiting function.

As far as I'm aware, those VW style tin can type VR's only have two solenoid coils that each operate a set of points. One (normally closed) set of points is on the voltage control coil and the other (normally open) is the cut-off relay, otherwise known as the reverse current cut-off relay. If there's a current limiter then there would be a third coil.

So my guess is that the current stamped on the outside of the tin box is the maximum current rating that the device can handle. So it should be OK to replace an 11 Amp VR with a 30 Amp one.

This vid gives a good explanation of how a 3-coil controller works ...


As you can see, the RCCR and voltage coils are essential to the basic operation of the thing.
The current limiter is not necessarily required if the maximum generator output is not sufficient to overload anything.
So if it's a 2 coil regulator, the current limiter will be the one that's missing.
 
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