Sport Pilot Talk

I have a 2009 912 uls in a Remos GX, and it runs like a top but when it is running the output voltage is 10.5 volts at ALL RPM's. I have changed the voltage regulator twice and have checked them for proper output and they are working perfectly. Any suggestions? If the generator was not working properly then it would not run as there would be insufficient voltage to the ignition modules right?

Thank you

Ray

restlinbaum wrote:I have a 2009 912 uls in a Remos GX, and it runs like a top but when it is running the output voltage is 10.5 volts at ALL RPM's. I have changed the voltage regulator twice and have checked them for proper output and they are working perfectly. Any suggestions? If the generator was not working properly then it would not run as there would be insufficient voltage to the ignition modules right?

Thank you

Ray

The ignition does not rely on system voltage for operation. You can have a problem with the power generation part of the generator, and still have the ignition work.

I did do some instructing in a Remos this past fall, and it also had electrical issues. At low power settings the low voltage alarm would go off. I was told that it is a known issue, and that there is a wiring harness fix for the problem.

I fly a Remos GX and get low voltage alarms all the time at low rpm, but never at high rpm.

low volt lamp flashes in my Sportstar as well, at low throttle setting. Goes away once throttled up to fly.

This low voltage alarm is at all RPM's. I also changed the wiring harness.

Ray

Cruise rpm should result in about 13.7v to 14.0v in my experience.

Have you checked your battery? Maybe run the engine it with a battery of known quality?

The real ROTAX mechanics might have specific suggestions for testing output directly from the alternator and into and out of the voltage regulator. Troubleshooting should also be in one of the Maintenance Manuals, available online. The culprit has been tracked down to corroded or otherwise compromised connections in the multi-pin connector to the Ducati voltage regulator, if that’s what you have.

Good luck. It’s a pretty simple system so should not be that hard to track down.

Where are you reading the 10.5 volts from? After a flight with the voltage at 10.5 does your battery have enough charge to start your engine?

3Dreaming wrote:Where are you reading the 10.5 volts from? After a flight with the voltage at 10.5 does your battery have enough charge to start your engine?

Great question, I dont think 10.5 volts would even start the engine. I'd measure it at the battery with a voltmeter and at the voltage regulator itself and see what you get.

Clean your ground terminal. Solder your VR connections (don't use crimp connections.) REMOS has a procedure. (NOT-002 Grounding). Look at their web site for procedures https://remos.com/?lang=en . They will also sell you a new wiring harness for $1500. Contact Skybound Aviation, LLC – Glenn “Mac” McCallister
Cape Girardeau Regional Airport
4333 John E. Godwin Jr. Memorial Drive
Scott City
Missouri 63780
phone: +1 573-833-0426
web: http://www.flyskybound.com
email: flyskybound [at] gmail.com

A new wiring harness has been installed by the mechanic. The battery voltage (on my Dynon) reads 10.5 volts when running. The plane starts up after each flight and I use a battery tender after each flight and when I check the voltage at the battery it reads 12.5 volts after charging it. The battery is new (2 weeks old) so it should be good.
Ray

restlinbaum wrote:A new wiring harness has been installed by the mechanic. The battery voltage (on my Dynon) reads 10.5 volts when running. The plane starts up after each flight and I use a battery tender after each flight and when I check the voltage at the battery it reads 12.5 volts after charging it. The battery is new (2 weeks old) so it should be good.
Ray

Battery voltage of the battery after a flight before the battery charger would be more helpful.

restlinbaum wrote:A new wiring harness has been installed by the mechanic. The battery voltage (on my Dynon) reads 10.5 volts when running. The plane starts up after each flight and I use a battery tender after each flight and when I check the voltage at the battery it reads 12.5 volts after charging it. The battery is new (2 weeks old) so it should be good.
Ray

Not an answer for you but wanted to simply point out that my battery voltage at the battery is always within a 1/2 volt higher than what my Dynon D-120 displays so a difference might be acceptable. Still doesn't explain your issue.

Is there a way to VERY CAREFULLY read the voltage at the battery AND the VR with your voltmeter with the engine running? And let me reemphasize VERY CAREFULLY.

Make sure to check the voltmeter too. It could just be a failed gauge or electronics.

I drilled a small hole on the firewall and ran the volt meter wires from the meter on the left directly to the battery. The meter on the right is measuring the voltage at the cig. lighter in the cabin. This is airborne at 5200 rpm. Note the state of the art free Harbor Freight multi-meters.

Before flight battery voltage is 12.5, after flight it is 10.5 volts. I know it is 10.5 volts in flight as the Dynon cuts out and goes to backup battery, radios cut out, and GPS cuts out and goes to back up battery.