Fuel level sensor

[jdeas]

I have the Vans supplied resistive fuel floats in my tanks. I don't like the size or look of the Vans supplied fuel gauge so I have decided to replace them with bar meters. Can anyone tell me what current the Vans meter ran through the resistive sensor? The new meter will be a simple current source but having no experience with fuel sensors I would like to get some feedback on any safety issues.
Currently (pun intended) I plan to use a 1ma current source to feed the tank sensors and simply read the voltage.

Am I doomed to explode?

 

[Jeff R]

The float sender varies from about 32 Ohms in full to 240 Ohms on empty. The current through the sender will depend upon the voltage. If you send normal bus voltage through it, you will have around 425 mA of max current, so it is best to drive it with a low voltage to keep the current down.

 

[Mel]

As Jeff says, the resistance of the pick-ups is approximate. They are not precise from sender to sender, so your set-up will need to have a method of calibration if you want them to be very accurate.
I have the EI gauge and it seems to be very good. It tracks along with my fuel flow very closely.

 

[jdeas]

Rethinking the design

Well, I was going to use a current source but if it shorts the current would go up through the sensor. It is overkill anyway.
I will just use a resistive divider and a ADC.

Thanks for the resistive values,
JD

 

[n82rb]

how about a lm3914 bargraph driver chip.

bob burns
N82RB

 

[az_gila]

How about one of these?

http://www.aircraftspruce.com/catalog/inpages/fl100level.php

I have a resistive one (the FL-100-R) unused and never installed. It works with the Vans resistive sender, and is calibrated in place to remove the resistive errors mentioned above.

Make me an offer....