Hunter 49 Autopilot turns when Microwave on

[Romagic]

I have a 2008 Hunter 49. When steering with the autopilot, the boat makes a sharp turn when the microwave is turned on.

I have found another Hunter 49 with the same problem. It sounds like a defect in the boat.

Is there anyone else out there with a Hunter 49 or Hunter 50 with the same problem? Has anyone found a solution?

 

[Don S/V ILLusion]

Sounds like a voltage drop problem for which the boat type is irrelevant. You should be able to verify this simply by monitoring the voltage at the autopilot when you turn on the microwave.

They are pretty sensitive to voltage.

 

[Romagic]

I have done this. The voltage does not change at all.

The heading on the autopilot compass does not move when the microwave is turned on, that is, the boat thinks it remains on course.

 

[RHUMB RUNNER]

I know a 49 owner in Marina Del Rey with this problem, I have the same problem with my 2009 49 when you use the electric winches. I have not tried the microwave. Some people believe it's because the fluxgate compass wire runs along side the house bank wiring, just a theory at this point.

 

[Don Lucas]

I have done this. The voltage does not change at all.

The heading on the autopilot compass does not move when the microwave is turned on, that is, the boat thinks it remains on course.

Your voltage doesn't drop when you run your microwave??????????????????

How big is your battery bank bank?

 

[Don S/V ILLusion]

I have done this. The voltage does not change at all.

The heading on the autopilot compass does not move when the microwave is turned on, that is, the boat thinks it remains on course.

I'm trying to understand what you must think is obvious... That being how the voltage cannot change measurably when you apply the rather significant load of a microwave. How did you measure that?

 

[Calif. Ted]

I've discovered that a microwave oven within 25' will make my XM radio go quiet, not sure what's happening but the working part is called a "Magnetron" and it's effects extend beyond the oven.

 

[artboas]

This is not possible

I have a 2008 Hunter 49. When steering with the autopilot, the boat makes a sharp turn when the microwave is turned on.

I have found another Hunter 49 with the same problem. It sounds like a defect in the boat.

Is there anyone else out there with a Hunter 49 or Hunter 50 with the same problem? Has anyone found a solution?

There is no way that your battery bank is staying at a constant voltage when firing up the microwave, unless you are running it from a genset. So, is your generator on, or running through inverter??

 

[Romagic]

I will check the voltage again when I am on the boat this weekend, but the batteries are new and the microwave should not drive the boat off course. I spent a while trying to track down the problem with an electrician. We tried with the boat plugged in and not to see how the microwave impacted the autopilot and tried running other things that drew a big load. We came to the conclusion it was not a voltage issue.

Wouldn't voltage cause the autopilot to turn off, and not simply make it shift its sense of direction?

We were coming to the conclusion that it was the location of the compass, although I know others think it is the location of the wires.

My thought on the matter is the Hunter should not sell a boat where the autopilot goes significantly off course when the microwave is on, and if they did, they should fix it.

It seems like it could be pretty dangerous.

 

[dziedzicmj]

I am going on a limb here, but is it possible that the interference from the microwave oven (it runs at 2.4 GHz) which can be significant within 1-2 feet from the oven is affecting the fluxgate? Especially, if you have a poor quality of malfunctioning microwave?

Microwave ovens were often causing interference with older Wi-Fi systems (operating in the same frequency band). It is possible that in the close quarters there might be interference with the fluxgate compass.

 

[Brezzin]

I know I'm a little late for this thread but I had a similar problem when running my electric winches. I think there's a thread here about that. Anyway I moved the flux gate compass about 15 inches to starboard in the same locker and my problem went away. My hypothesis is that a heavy load on the battery creates a small magnetic field around the forward battery. This distorts the compass which is pretty close to that battery. By moving the compass outside that field then no distortion. Now I don't know if my hypothesis is correct but I do know that moving the flux gate stopped the "crazy Ivan's" the autopilot was doing.

 

[James10016]

Romagic,

Honestly, I'm still going with the voltage drop caused by running your microwave too.

They typically draw up to 10+ amps when you turn them on. The Autopilot itself, can also draw up to 10 Amps during normal operation. That's a pretty hefty load if they both 'peak' at the same time.

On my boat the B&G autopilot(network pilot) has a 'Rudder Reference Unit (RRU), which is a sealed high specification potentiometer, it determines it's pointing by measuring voltages in the sensor at the 0.10 volt level. You can measure the voltage difference between the green and blue wires of the RRU, which should show a minimum of 1 volt change from hard over to hard over. It is also here at this same connection that You could connect a Voltmeter and determine 'IF' there is a current fluctuation (spike) when you Turn Your Microwave ON/OFF. Keep in mind it will only take a 0.1 volt change to throw it off, when you turn the Microwave ON. You can perform this task while tied up safely at the dock.

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Now my Network Pilot 'glitches' now and then, but especially when the house battery starts getting low, which makes it more sensitive when a major electrical appliances is being used, such as the normal on/off cycling of the refrigerator.

Good Luck with yours!

James