Autopilot Power Supply

[Neil McDonald]

I have just received my new Autohelm S1 package which is to be fitted as an upgrade for an elderly ST4000. Reading the S1 manual, I see that it says not to feed it power from the engine starting battery because reduced battery voltage during engine startup may throw off the S1 settings. As far as I know, the battery selector switch selects the power source for everything on board - either house battery, starter battery or both working together. So when I select the starter battery for an engine start, the whole boat gets this power source.....and also any associated voltage drop. Is it really worth the effort to wire in a direct house battery only power supply to the autopilot breaker on the main electrical panel?

 

[ernie]

in a word....yes!

I experienced what the manual tells you about. Isolate your batteries and you're on the right track. Of course the easy way out is to not power up your autopilot until after you start your engine.Another bit of advice, if I may, lose that "1-2-both" battery switch. With the batteries isolated the only thing the engine battery ever has to worry about is starting the engine. There's a great diagram of this set up in the WM advisor.

 

[sailaway78]

Auto Pilot Wiring

I have all my electronics power running from a seperate breaker. This way I can leave all of it off, until needed. The way mine is wired, is from the breaker, to a fuse block, with the required size fuses for each instrument. Then to the individual units themselves. The modern electronics are getting more and more particular about voltage, and lots of other things. Friend of mine with a new S1 pilot recently had his start turning in circles. After many phone calls, and a lot of investigating, someone told him to unplug the rudder sensor for a couple of minutes, with the pilot powered up. VIOLA Something in the system reset itself, and it has worked perfectly since.