MGL Avionics User Forum

So my understanding is that the MGL Extreme EMS will accept a signal from the fuel level sender either as ohms or as voltage depending on the RADAC switch setting. I'm debating using one of the cheaper float types versus the capacitance type MGL has on their website (which costs 10 times more) if I can. If I can't, has anyone used the MGL sender and if so can the outside of the probe touch the metal fuel tank? It mentions that the signal it sends to the EMS varies with the fuel between the outer and inner tubes, so I'm thinking the outer tube touching ground shouldn't affect it, correct?

VacaMoo wrote: ↑Sun Oct 29, 2023 9:41 pm So my understanding is that the MGL Extreme EMS will accept a signal from the fuel level sender either as ohms or as voltage depending on the RADAC switch setting. I'm debating using one of the cheaper float types versus the capacitance type MGL has on their website (which costs 10 times more) if I can.....

The float type works reasonably well, depending on the shape of your tank.
The issue is positioning the float arm so that the float can swing from full to empty without mechanically topping or bottoming out.
If not, best to set it so you can reliably measure tank levels at the bottom/empty end, and let it hit the stops towards the top/full end.
Given that you dip your tanks prior to flight, you know your fuel load to start with. It is the fuel load you finish with that is important to monitor in flight!

The float type I was considering using is this one where float goes up and down the shaft so it's not prone to getting stuck like the ones with an extended arm float. https://www.amazon.com/BLLYOGU-Sending- ... RZBVG?th=1

Having said that, today I realized that where I'm going to install the sender I might not be able to use the float type due to being a very small opening where the float won't pass through, so I might have to use the sender like the one that MGL sells https://www.michiganavionics.com/produc ... el-sender/

1st question : Has anyone used this MGL type fuel level sender and how short can I cut it? I only have approximately 5.5 inches of tank depth. I'm going to email the company that makes them to see how good their technical support is.

​2nd question : If I have to install the sender upside down from the bottom of the fuel tank up into the tank (it has one place where I could install it without having to modify practically anything), would it work upside down? I imagine that since this sender only gives ohm readings as the fuel contacts it as the level goes up or down, as long as I enter the correct values in the MGL Xtreme EMS then it won't know if it's right side up or upside down. I can always swap the high and low alarm wires, right?

3rd question : Can I use different types of senders for each wing? In other words can I use a float type for one wing and a "float-less" sender for the other wing? Does the MGL Xtreme EMS program each tank independently? Not sure I'd leave them for final use because you don't know which would be more precise but for testing it would be great if I could do that. I could buy a cheap sender and an expensive sender and do many tests and when I'm done testing buy the expensive ones already cut to the correct lengths.

Does anyone here use fuel senders with their MGL Extreme EMS?

Here are some of the answers to the questions I asked here previously that I've been able to find elsewhere, so maybe it'll help someone here who decides to do this in the future:

1- I contacted the company who makes the senders and they told me they can cut it to almost any length, just let them know when you order it.

2- The manufacturer told me that the senders are not sealed so installing them upside down would make them leak fuel.

3- The last question has been asked to many who have the Extreme EMS on other forums but no reply up to now. It seems nobody knows how MGL works in this regard. I suppose this might be due to so many people buying experimental planes just because they're cheaper or more efficient than buying a standard category plane, so not many people actually experiment with anything that's not neatly boxed and plug-in anymore.

If anyone knows how the MGL Extreme EMS handles fuel senders, please advise.

I'm not sure what answer you are after - there is no magic when it comes to measuring fuel quantity from a sender.
The instrument measures voltage. In cases where the sender is passive it tends to be just a variable resistor to ground so you can switch a pull-up resistor in line to a 5V source. So you still measure voltage. Nothing really changed.
The rest is up to calibrating the system - you have a total of 6 points from empty to full - you can see what the instrument is currently measuring - it's just a number but it really does represent voltage. Once you set the tank size you will be presented with calibration points - for a 50 liter tank you will have 6: 0,10,20,30,40 and 50 liters. So now you fill the tank in those steps and copy the reading into the relevant slot. This to a large extent caters for your tank shape. There is a filter you can set which tells the instrument over what kind of time period to average the readings - that helps to get reasonable behavior if there is a lot of sloshing going on inside your tank.

That's pretty much it.

Consider "lying" slightly when is comes to fuel tank size - example: You have a 60 usable liter tank. Make it a 50 liter tank and start the zero point with 10 liters already in the tank. That's your "reserve".

This is what I'm still looking for and why:

3rd question : Can I use different types of senders for each wing? In other words can I use a float type for one wing and a "float-less" sender for the other wing? Does the MGL Xtreme EMS program each tank independently? Not sure I'd leave them for final use because you don't know which would be more precise but for testing it would be great if I could do that. I could buy a cheap sender and an expensive sender and do many tests and when I'm done testing buy the expensive ones already cut to the correct lengths.