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overvoltage & battery not charged well
https://ukbeg.com/forum/viewtopic.php?f=8&t=15598		 Page 1 of 1
Author:  gunter [ 01 Oct 2012 19:49 ]
Post subject:  overvoltage & battery not charged well
Ladies, Gents, suggestions please!

Diagnosed slight overvoltage (15.5 - 16.5 volts when riding, 14.4 volts in idle) and battery is discharging slowly while riding. Not really discharging, but seems not get charged, because it is losing power with every start. Borrowed a new battery at Oschersleben after the bike started clicking - just to make sure - and on my ride back (220 mls) noticed that this one behaved similar like mine.

Stator resitance is infinte to ground for all phases, phase-to-phase is 0.1 - 0.2 ohms, so wires seem okay, alternator delivers 20 volts per 1000 rpm, which sounds promising too. Didn't dare to check connector 77, as I know, that one is not forgiving, but do not have any suspicions that this one might be the culprit.

Now, how to proceed? Replace VR on spec? I'm definitely going for an aftermarket part then, still waiting for a response from the swiss forum, where some people did the same.
Author:  WILLYBUELL [ 04 Oct 2012 22:15 ]
Post subject:  Re: overvoltage & battery not charged well
some thoughts from brian ,his opinion is you have a diode down in your rectifier ,you volage readings are high because your readings are being bumped up with intermitent AC from your poorly diode ,two tests,1 is your battery getting warmer than usuall on a ride ,if so this due to the intrermitant AC your possabley getting .2 put an ammeter in the chargeing wire to the battery,you should get a reading if battery is draing through the rectifier to earth ,this needs to be done with the ignition swtched off ,hope this is helpfull ,keep us posted how you are getting on dude :yup:
Author:  gunter [ 05 Oct 2012 18:03 ]
Post subject:  Re: overvoltage & battery not charged well
With ignition switched off, there's a current of only 40 mA flowing, which is probably keep-alive for the ECM and the instrument cluster.

I compared ECM output to a multimeter readout, these two show a voltage difference of 0.5 volts - so whom to believe? I also redid all ground connections I was able to reach, and the starter sounds more powerfull now, a part of the problem seems fixed now. But I still don't know, what's causing the overvoltage and why the battery isn't charged well.

Battery voltage is (all values are multimeter readouts):
- 12.3 volts with ignition off
- 12.1 volts with ignition on (headlight and tail light on, fuel pump off)
- 10.5 volts when cranking (ECM fuse pulled, no fuel pump, no injectors, no ignition)
- 14.0 - 14.5 volts when idleing
Author:  mundoxan [ 05 Oct 2012 18:18 ]
Post subject:  overvoltage & battery not charged well
Normally if you read over voltage the caused will be the rectifier. Could you borrow a rectifier from another bike?
Author:  WILLYBUELL [ 06 Oct 2012 18:40 ]
Post subject:  Re: overvoltage & battery not charged well
gunter wrote:
With ignition switched off, there's a current of only 40 mA flowing, which is probably keep-alive for the ECM and the instrument cluster.

I compared ECM output to a multimeter readout, these two show a voltage difference of 0.5 volts - so whom to believe? I also redid all ground connections I was able to reach, and the starter sounds more powerfull now, a part of the problem seems fixed now. But I still don't know, what's causing the overvoltage and why the battery isn't charged well.

Battery voltage is (all values are multimeter readouts):
- 12.3 volts with ignition off
- 12.1 volts with ignition on (headlight and tail light on, fuel pump off)
- 10.5 volts when cranking (ECM fuse pulled, no fuel pump, no injectors, no ignition)
- 14.0 - 14.5 volts when idleing

HMMMMMM ,willl see brian tomoz ,see what he thinks ,which bike is the problem on mate ,will be helpfull info :yup:
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