Aprilia Voltage Regulator

[DavidHill]

Hi,

I am confused as to whether my voltage regulator is working and whether I have wired it correctly.  It is a Bosch regulator 9190 040 099 and currently when I run the car there is around 16-18V at the battery terminals when the car is running at around 1000 rpm.  All the advice on the internet states that over 14V is too high and could damage the battery.  I have tried two other Bosch regulators and get the same voltage at the battery (16-18V)...is that the right voltage or do I need to change something??  I have connected B+ to the battery, 61 to the fuse box and D+ and DF to the Dynamo.

David.

[lancialulu]

Are you using a digital voltmeter? If so Try an analogue one - they are much more resistant to hi RFI under the bonnet of an old car ignition system

[davidwheeler]

These old regulators can be adjusted as well.   There are two circuit breaker springs within, one for the cut out and one for the voltage.   They are tensioned by adjustable screws.    By trial and error you can work out which is which!     Normally you would want 14.7 volts across the battery terminals.

[DavidHill]

Thanks for the replies on this.  I don't think the regulator needs adjusting as I have also tried a Bosch solid state regulator with the same results - I still get 16-17v at the battery. I am using a digital multimeter though...interference from the engine does make sense as when I put the multimeter on top of the engine it does go haywire! (It is much more stable on top of the battery). I will try and borrow an analogue one and see if that reads 14v.  Will keep you updated!

[DavidHill]

Found the issue.  I made a small faraday cage to put the multimeter in and it still showed 16-17v, so discounted interference.  I then unbolted the voltage regulator completely from the dynamo and isolated it from it (but it was still wired in).  That fixed it!  Essentially the dynamo is transmitting unregulated voltage to the B+ output via its casing and the attachment bolt...so all i need to do now is attach the regulator but make sure it is not attached with anything that conducts ... Thanks for all the advice!