Power drain causes over voltage from alternator

[Johninreading]

My bike runs OK but the alternator is outputting 16.5V at all revs. I've traced this to a power drain on the battery which drops the voltage from 12V to about 9.5V causing the RR to think the battery is low, so keeps supplying current to the field winding of the alternator (hence the hight voltage output from the stator).

The power drops when I connect the electronic ignition (Newtronics) to the coils. With the electronic ignition powered up but disconnected from the coils, the voltage returns to 12V. So it sounds like the EE could be at fault. Has anyone seen this before and is there a way to test this EE system?

[barney01]

Hi
I have a 550 with Newtronics ignition which has been on the bike for 20 odd years. IMHO it is highly unlikely to be the cause of your problem they really are that reliable.
The usual cause of overcharging is faulty connections and bad earth's between the battery and alternator. As you correctly state, the sensor wire which detects the battery voltage misreads because of bad connection and tries to catch up overcharging the battery.
If you are convinced it is the Newtronics kit why don't you give them a ring? They are very helpful and give advice freely over the phone. I have done so before
http://autocar-electrical.co.uk

[Johninreading]

It was not the ignition, as you stated. It was poor wiring (reg was wired to the run/kill circuit). It seems to be working now.

Regards
John

[barney01]

Result!