Lithium-Ion 18650 and magnetic interference

Has anyone here had success with 18650 battery cells on relatively small (<4kg) quadcopters?

I have a lot of problems with magnetic interference from the 18650 batteries and have not been able to create enough space between the battery and the compass on a small multirotor. Does anyone have a practical solution to this kind of problem? My impression is that there are several drones that use 18650 batteries.

Get a gps mast to move it up and away from the vehicle.

I used a Li-ion pack on a sub 250g 4" for awhile. Do as @geofrancis suggested and use the Magfit utility in MAVExplorer for compass calibration and compass motor interference.

I will check out the magfit utility. I have no problem to do a successful mag-calibration with one battery. The problem is when I change battery and the new battery requires a new calibration.

When monitoring the mag-field reported from arducopter, I see that i need at least 30cm distance between the battery and the compass before the magnetic field from the battery makes a low impacton the measurement. How did you solve that on a sub 250?

GPS masts are only a couple of dollars and will get your compass far enough away from any interference.

I didn’t. Magfit worked quite well and I only use 1 battery.

My sub250 3 "with gps, compass, VTX, optical flow, has no problems with 2 18650 and flies almost 15 minutes

So, the solution is either enough distance between the compass and the battery, or to use only one battery which can be compensated for with compass calibration. Got it!