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  #1  
Old 10-11-2018, 05:11 PM
Speedbird1 Speedbird1 is offline
 
Join Date: Jan 2018
Location: San Antonio, TX
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Default Fuel Capacitance plates / Dynon issue ??

Hello -

I have an issue with incorrect fuel tank readings. The (Vans-supplied) plates are connected to a Dynon Skyview via the Dynon capacitance to voltage converter. A calibration has been done and minor changes (0.01-0.02 volts) were noted at the 2 gallon intervals pours. There is an old thread out there which suggests the use of Princeton Electric Plate converters.

Does anyone have experience with these or any advice to offer regarding the situation?

Thanks for any advice.
Gary.
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  #2  
Old 10-11-2018, 05:28 PM
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BruceEicher BruceEicher is offline
 
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I have your same set up for six years. I have found that a poor electrical connection at the tank to converter will give me a false reading, sometimes even an empty tank reading. The connection plug that passes thru the tank can leak a drop of fuel over time making this poor connection. For me it has only been on one wing tank and a spray of cleaner will clean it up and restore the gaugeís readings. Now just part of the yearly service list.
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  #3  
Old 10-12-2018, 09:29 AM
Speedbird1 Speedbird1 is offline
 
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Quote:
Originally Posted by BruceEicher View Post
I have your same set up for six years. I have found that a poor electrical connection at the tank to converter will give me a false reading, sometimes even an empty tank reading. The connection plug that passes thru the tank can leak a drop of fuel over time making this poor connection. For me it has only been on one wing tank and a spray of cleaner will clean it up and restore the gaugeís readings. Now just part of the yearly service list.
Thanks for the information. Is there any chance you can post your voltage readings for the levels? Mine are SO close together and I was wondering if yours are any different.

https://www.dropbox.com/s/hjtfmaanau..._7673.JPG?dl=0
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Old 10-12-2018, 10:43 AM
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Raymo Raymo is offline
 
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Your experience is normal. The changes between pours is small but measurable and goes out many decimal places, which cannot be seen in the calibration screen.
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Old 10-12-2018, 12:47 PM
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BruceEicher BruceEicher is offline
 
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Quote:
Originally Posted by Speedbird1 View Post
Thanks for the information. Is there any chance you can post your voltage readings for the levels? Mine are SO close together and I was wondering if yours are any different.

https://www.dropbox.com/s/hjtfmaanau..._7673.JPG?dl=0
Sure, Iíll snap a pic tonight, but Ray is right...
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Old 10-12-2018, 02:29 PM
Speedbird1 Speedbird1 is offline
 
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Are both you guys getting accurate reading from the tanks? If we put 42 gallons in and burn 21, the fuel flow transducer is right on the money but the tank gauges will, for example say that there are 5 gallons left in the left tank and 7 in the right. Mis-match is a big delta.
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Old 10-12-2018, 04:51 PM
smithflys23 smithflys23 is offline
 
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Quote:
Originally Posted by Speedbird1 View Post
Are both you guys getting accurate reading from the tanks? If we put 42 gallons in and burn 21, the fuel flow transducer is right on the money but the tank gauges will, for example say that there are 5 gallons left in the left tank and 7 in the right. Mis-match is a big delta.
I have your exact issue as well. I think I am going to have to do another calibration.
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Old 10-12-2018, 06:04 PM
Aluminum Aluminum is offline
 
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Quote:
Originally Posted by Raymo View Post
Your experience is normal. The changes between pours is small but measurable and goes out many decimal places, which cannot be seen in the calibration screen.
This is not normal. On my setup I had to install a cap in series with the tank plates to bring the swing into the 0-5V output range of the Dynon converter. My plates are bigger than Van's though.

I suggest measuring the capacitance and resistance across the tank plates with a nice instrument to get a quantitative idea what's going on. There might be a short. Epsilon of gasoline is 2, so if your converter barely registers doubling of capacitance something is wrong.
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Old 10-12-2018, 11:30 PM
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BruceEicher BruceEicher is offline
 
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I did recalibrate after flying about 30 hours. Now I am within a gallon or two almost all times.
My dipstick is the most accurate, then my fuel flow red cube then my gauges, but close as a gallon or two.
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Last edited by BruceEicher : 10-12-2018 at 11:35 PM.
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Old 10-13-2018, 07:26 AM
Speedbird1 Speedbird1 is offline
 
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Thanks for posting this. I appreciate it. You are using the Dynon Capacitance to voltage converter, correct? Also, do your plate look like this:

https://www.dropbox.com/s/eihqsho9e4...40018.jpg?dl=0
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