fuel calibration 18+

[rlallen1]

Hello again, yesterday I calibrated my fuel tanks/readings in dynon sv per the instructions. I input max fuel was 21 gallons, started with 0 and added 2 gal at time. Once the tank was full and I had completed the calibration I checked the fuel input on the SV screen and it was up a little more than 3/4s and said 18+. I had expected it to be all the way to the top and say 21. Did I do something wrong or is the normal?

 

[schristo]

Assuming you have a float sensor located near the root of the wing this is normal... once the float is against the top of the tank the reading is at its maximum but there remains a significant volume over this amount from the wing angle and tank geometry. all that the sensor 'knows' is that their is more than the maximum calibrated volume; in your case 18 gallons. for my tanks, the left has a standard pick up and reads a maxim of 16 gallons and the right has a flop tube which moves the location of the float outboard and the maxim reading is 17 gallons. I am surprised that you see 18.

 

[rlallen1]

I have capacitance plates in the tanks..not float type. I calibrated up to 21 gallons..still shows 18+...I suspect this isn't an issue since once the readings below 18 the gauge is reflecting correctly. I was surprise though it didn't go to 21 max..

 

[schristo]

hmmm... I thought that the capacitance plates would calibrate to full... look at the recorded calibration points that are stored in the Dynon (export the settings file). You can plot the points in Excel to see how well captured the data is, also you can take a look at the sensor data when you are full to see if the sensor is maxed out or if you just need to add another point to the settings file at full (then import the file back)

 

[mmarien]

You could have missed the last point. It's not clear what you should do with the last add. Press add or press full? I think you are suppose to press add then full. You can add a point without recalibrating as Stephen says. Go back to the calibration screen. It will tell you the voltage of the current level. Compare that with the calibration data in the settings file and add a point or adjust the data.

I like my new capacitance type sensor. It seems stable and accurate. My previous float sensor had three levels. Full, some fuel and could be near empty. You could get any one of those readings at any time depending on the pitch. :

 

[rlallen1]

ah...thanks stephen and mmarien, you are right. at the last point I hit full. I should have hit add, then full.

 

[rlallen1]

to close the thread...I recalibrated my tanks last night. this time on the last fill I hit ADD then Full. Fuel guage problem fixed..thanks stephen and mmarien

 

[johnsteichen]

You do not want your fuel gages to be too accurate, because you might be tempted to rely on them. You only want them correct at E. Know what you put in, and know what you are using