Charging fault

[jchesshyre]

Trying to pin down why my charging system isn't working. It's been gradually failing to charge the battery and now isn't doing so at all.

Resistance between each of the three yellow wires from the alternator is in spec at 0.5 ohms, but all three show continuity to ground with almost no resistance (in fact about 0.5 ohms too). This is with the battery disconnected btw. The connector block from the alternator looks a bit burnt too.

If I measure the AC voltage directly from the alternator between any of the three wires it's about 20V at idle rising to around 60V at 5k rpm. To me this suggests the alternator is fine and the reg-rec is faulty (it's a finned Ducati one that was on the bike when I got it at 29k...now on 110k so I wouldn't resent it if it had failed!). Yet why the continuity between all three alternator wires and ground, and why the slightly charred connector from the alternator??

[sirch345]

Trying to pin down why my charging system isn't working. It's been gradually failing to charge the battery and now isn't doing so at all.

Resistance between each of the three yellow wires from the alternator is in spec at 0.5 ohms, but all three show continuity to ground with almost no resistance (in fact about 0.5 ohms too). This is with the battery disconnected btw. The connector block from the alternator looks a bit burnt too.

If I measure the AC voltage directly from the alternator between any of the three wires it's about 20V at idle rising to around 60V at 5k rpm. To me this suggests the alternator is fine and the reg-rec is faulty (it's a finned Ducati one that was on the bike when I got it at 29k...now on 110k so I wouldn't resent it if it had failed!). Yet why the continuity between all three alternator wires and ground, and why the slightly charred connector from the alternator??

That doesn't sound right to me, I can't see you should be getting continuity between all three yellow alternator wires and ground

I had issues with that terminal block connector on the end of the yellow alternator wires see link:
viewtopic.php?p=492892#p492892
I think any resistance at the terminals there, or at the rectifier cause heat to build up, hence the burn marks, or as you suspect a fault with the rectifier itself,

Chris.

[jchesshyre]

Seeing as the bike has 110,000 miles on it I thought to hell with it and have ordered a MOSFET reg rec and a £90 stator from Wemoto. .. will report back ...

[sirch345]

Seeing as the bike has 110,000 miles on it I thought to hell with it and have ordered a MOSFET reg rec and a £90 stator from Wemoto. .. will report back ...

That sounds like a good idea considering the mileage covered

Do let us know what you think of the new stator once you have it all working again

Chris.