View Single Post
Old 07-10-2017, 08:29 AM
John-G John-G is offline
Join Date: Jan 2012
Location: Northeast Ohio
Posts: 535

Jack -- Judging by the description of your high current event I would suspect it was a result of a slightly low battery. The Rotax engine's power source is not like an automotive alternator where fairly high current can be obtained at fairly low RPM's. The Rotax engine won't produce full electrical power at lower RPM's which is why after the run-up you saw the current go negative because the battery needed to supply the difference hence the negative amps until you bumped up the engine RPM. As the battery became fully charged during the flight, you saw the current drop over time. This is what would be expected ... so it sounds like you experienced a normal event of charging the battery which apparently was not at a near full charge when the engine started.

It appears the majority of builders that have experienced voltage regulator problems have had a precursor event(s) typically intermittent charge current or sometimes a high voltage. More typical is an event where the charge current bounces around and goes negative then seem to cure itself after the flight has been completed and the regulator cools down. It has been speculated that the solders inside the Ducati regulator get hot enough to become melted then as the solder cools, it reconnects the circuit and all appears well again. Personally I feel the Ducati regulator is a tad anemic for the task we ask of it ... it certainly could benefit from more heat sink fins and a redesign of internal connections.

I just recently finished up relocating a Silent Hektik F4118 regulator on a modified "Bender baffle" inside the air duct in the lower cowl. Unfortunately, have not got the bird in the air yet to see how well that will work out so can't give any advice about the relocation one way or the other yet. I'm hoping the regulator will be subjected to less vibration than on the firewall shelf and for sure there will be the added benefit of an abundance of cooling air ... so I'm very hopeful it will be a win -win.
RV-12 Wings, Empennage, Fuselage, Finishing, Avionics and Powerplant kits all completed
Now Flying!!

Dues paid until September 2019

Last edited by John-G : 07-10-2017 at 08:54 AM. Reason: added text
Reply With Quote