MGL Avionics User Forum

I have an MGL Extreme EMS installed in the RANS S-21 Outbound I am building. Titan 340 engine. While other parameters display properly on my screen I'm struggling to get the MGL magnetic current sensor to work. Question 1: It goes on the main lead coming off the alternator, correct? Question 2: No matter which way I orient the sensor on the wire, above, below, backward, forward, the display shows a figure in Amps but the value always INCREASES when I load the system, i.e turn on strobes, nav lights boost pump. Anyone have any suggestions? Thanks

You did zero the reading with the sensor NOT near a cable ? That is needed to get the zero point exact.

You can read the voltage on the signal wire with a volt meter. The zero current point is 2.5V - from here it either increases or decreases depending on direction of the current. The amount of the change is determined by the strength of the magnetic field created by the current and just how you "connected" the wire to the sensor (details in the manual) - you "calibrate" this in the EFIS by using a reference such as a amp meter you wired in series on a temporary bases (some just thumb suck it until it "looks right"). It's quite a flexible way of measuring the current as you can scale it to almost any range you fancy.

Now the lead from the alternator is likely not a great one - the reason is that you do not get a constant DC current - the alternator is A/C so you get rectified A/C - pulses in other words.

The proper place would normally be the feed to the battery positive (or you can consider the negative as well). That way it shows change/discharge.
If you are only interested in what your systems use - look at the positive feed to your loads (after the alternator connection which usually goes directly to the battery positive). In this case the alternator current is "don't care".