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Old 03-03-2015, 07:03 PM   #1
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Voltage on Tank Sensors

Does anyone know what voltage should be on the tank sensors when the tank is full and empty?

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Old 03-03-2015, 07:12 PM   #2
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I think 12 volts dc because it works if you are not plugged in to "shore" power.'s only "hot" on one of them. The others are the other side of the circut. The " stuff" inside completes the circuit.

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Old 03-03-2015, 07:26 PM   #3
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Not sure you will have much luck checking voltage, the sensors are usually connected to op amps that simply look for low current ( completed circuit) between the level sensors.

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Old 03-03-2015, 07:56 PM   #4
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Originally Posted by oakprk View Post
Does anyone know what voltage should be on the tank sensors when the tank is full and empty?
Here is what I have on the sensor array. You would need to do the math to calculate a voltage from your actual battery voltage and the drop across the individual resistor pack.

A Full indication is zero ohms (short circuit) so zero volts read.

An Empty indication is resistance above 188K Ohms, so voltage read would depend on input voltage.

ANY probe shorted to ground (the white wired probe) by slime, hair, or crud touching the tank walls will read a full tank.

See my review on Horst Probes here Horst tank Probe Installation

And a film of why you need to upgrade your probes here:


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