Electrical issue

kloudie1 · Nov 26, 2012

yep..low volts at the autopilot. bad or dirty connection or several.. check battery terminals first then check main buss connections and the grounds too..

Don S/V ILLusion · Nov 26, 2012

You obviously can measure the voltage which is what I would do to determine if it is a voltage drop issue which is likely since these should not be on the same circuit. Before doing any rewiring, I'd check the voltage and EVERY connection in both circuits to ensure you don;t have a bad connection. Don't just look but actually remove and re-connect every connection as visual inspection usually just misleads people

Bill Roosa · Nov 26, 2012

Just like flushing the toilet while in the shower. On is on the cold water circuit and the other is on both. The MAIN cannot supply (rapidly) the new demand for water and the pressure falls off on other system.
Check the battery and circuit breaker connections first as those are the MAINs in this situation

Mike B · Nov 26, 2012

Like kloudie said, start at the battery. It's not uncommon to for the terminals to oxidize enough to create a voltage drop under heavy load. Clean all contact points even if they look OK. Dont forget to coat the terminals to prevent or slow down future oxidation.
Mike

kenn · Nov 26, 2012

another vote for kloudie's suggestions. Something in the wiring isn't conducting fully; I expect that if you monitor the voltage at the Autohelm's 12v input, you'd see it dip when the freshwater pump or other significant load is started.

sailaway78 · Nov 27, 2012

Ground first

Since they are on separate switches, it has to be at or before the switches. My bet would be on the ground side of the system.

Benny17441 · Nov 27, 2012

All good advices but in the spirit of geting back to basics, check the state of charge of your batteries and then move on to ground connections and circuits.

onecoolair · Nov 27, 2012

Also these wires for the auto helm electrical and data are very small gauge and if the wires had ever been kinked at any point say during the install. This could cause a week spot some where in the wiring . Check the entire wiring run for any breaks in the wire under the wire insulation.

Bill Coxe · Nov 27, 2012

And possibly water is running past the fluxgate compass. If my bilge pump kicks off while the autopilot is on I get a 10 degree course change and when the bilge is clear, I get ten in the opposite direction.

sandpiper10471 · Nov 27, 2012

I posted the same question about a year ago. I had just replaced the pressure water pump. The advice coming from this forum indicated it was likely radio waves transmitted by a bad ground at the pump. Now I| just turn the water pressure off when I am under autopilot. Some day I will check it all out.

Maine Sail · Nov 27, 2012

Stephen K said:
I have a peculiar issue on the DC side. My fresh water pump and Autohelm are on separate switches, but if both are "on" and someone runs the freshwater pump... it causes my Autohelm to "cycle" repeatedly like it does upon start up.

Is this possibly caused by a drop in voltage? Any ideas for a cause and for a possible fix?

Stephen,

Could be wiring but I'd also consider the magnetic interference when the pump runs. If the pump is close to your magnetic fluxgate compass then this could be the cause. Monitor the voltage at the AP motor and then cycle the pump. If it is not fluctuating below 11.8V or so it is likely fluxgate interference.