Voltage output concern

by Chuck Woods in 912 / 914 Technical Questions 13 years ago

When the RPM on my 912ULS is below 3500 RPM the voltage reading is less than 13.2 VDC. When running the engine above 4700 RPM the output is 13.7 and the amp indication indicates from -4VDC to +5 VDC. My engine is installed on a RV-12.

Re: Voltage output concern

by Roger Lee » 13 years ago

Roger Lee

128 5.28k 4.98k

Hi Chuck,

Pretty normal for many aircraft. People get all kinds of readings and yours is the same as many. It depends a lot on your electrical system.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: Chuck Woods

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Re: Voltage output concern

by bill martin » 13 years ago

bill martin

10 757 0

Chuck,

Mine runs at about 13.5V at idle (1800RPM) up to about 14.1 at 5000RPM. Very close to what you are running. One difference may be that I use very little power: usually around 3A total, or less.

Bill.

Thank you said by: Chuck Woods

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Re: Voltage output concern

by Chuck Woods » 13 years ago

Chuck Woods

3 3 0

Thanks for your input.

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Re: Voltage output concern

by David Sussman » 13 years ago

David Sussman

2 7 0

If you do not have an aux alternator, you may not have enough output from the built in generator(20 amps)to power your electric load until you get to 3500rpm. That's why you show a negative charge( amps coming from the battery to make up the difference).
David

Thank you said by: Chuck Woods

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Re: Voltage output concern

by Roger Lee » 13 years ago

Roger Lee

128 5.28k 4.98k

Normal amp variation is -3 to +3 as you fly and that isn't a low output number. Amps will always move around. It's rarely ever steady. That might make me more suspicious if it was ever steady.
The voltage should be close to steady, but may vary .2 volts.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell

Thank you said by: Chuck Woods

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Voltage output concern

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