Fluxgate Compass/Battery Selector Switch Interference?

[Ward H]

I'm thinking about moving the battery selector switch to a location that happens to be about a foot from the fluxgate compass for the ST4000 autopilot. This will shorten the 1/0 AWG runs to the switch by 30% to 40%.
The purpose is two fold. Get the switch off the swing down distribution panel and reduce voltage drop. (reduces VD to starter by 2%)
The ST4000 manual says not to mount near any large iron masses or magnetic items.

Will having the battery selector switch a foot or so from the fluxgate compass interfere with the compass?

 

[Hello Below]

Will having the battery selector switch a foot or so from the fluxgate compass interfere with the compass?

I wouldn't think there would be a problem but try it with a handheld compass before you make the move.

 

[LeslieTroyer]

I think it will cause problems, you want at least 3 feet from your compass (inverse square on the interference).

Try it by running a #8 from your charger to batteries about 9-10” away and monitor your “heading”. The reason for being closer is the alternator probably is higher amps.

Les

 

[LeslieTroyer]

Ask @jssailem what happened when he put a boom box over the cabinet with his course computer for his AP

 

[dlochner]

Get the Gemeco | Apps Install app. It has a magnetometer on it. Power up the current switch and measure the magnetic field. You should be able to see how far the field, if any, extends. That will give you an idea about the amount of interference you'll get.

 

[jssailem]

Oh it was fun.

 

[Ward H]

Get the Gemeco | Apps Install app. It has a magnetometer on it. Power up the current switch and measure the magnetic field. You should be able to see how far the field, if any, extends. That will give you an idea about the amount of interference you'll get.

Got the App. Pretty neat.
I'll see how much I can power up and check the switch.

 

[JamesG161]

he put a boom box over the cabinet with his course computer for his AP

ahhhh haaaa! So that is why you fell in the water on his boat!
Sneaky trick!
Jim...

 

[Ward H]

I decided not to move the switch. That location is to close to the compass and I haven't sailed the boat yet to know how well the AP works as is. (Worked during sea trial but that was a short test)

Since the boat was factory wired with #4 SAE cable, the 1/0 AWG I'm installing will already be a huge improvement, something like 7 or 8% reduction in VD.

@jssailem Here you go John. Maybe you can use this on top of the cabinet.



Thanks