auto pilot question

[Ken Cobb]

If a boat is equipped with solar panels and a wind generator, could it cruise under auto pilot (in normal seas) indefinitely, or would it still be necessary to run the engine every day to keep the batteries charged?I am trying to get at the question of how much power the typical auto pilot requires, and to determine the point at which a wind vane steering system would start to be worth the extra expense.

 

[John Visser]

It depends

Most of the power consumed is in the motor. The amount of work the AP does depends on many factors including boat balance, seas, variablility of winds, how well the boat tracks, and, believe it or not, what heading you are on (due to magnetic compass dip effects). Its therefore tough to say how much power would be used. Cruising ioffshore, you'll probably need power anyway, and will run the generator or engine daily. 'Fridge, radio, water pressure, lights, etc.

 

[Lee Hadjiosif]

Autopilot

The ST4000+ autopilot uses an average of one amp when in auto mode. So if your solar panel and wind generator can produce as much amps as you are using including the autopilot, you could operate indefinitely. You should also plan for those no wind and no sun days.

 

[Kevin]

Power Consumption

Ken:Take a look at the web sites. I'm not sure what you sail or what unit you are looking for. As an example the Raytheon ST3000 draws .7 to 2.5 amps depending upon load, just as John indicated. Calculate your total daily load, add for flub factor and consider efficiency of your power sources (eg; solar panel 60 watts x 10 hours x .8 (not always facing the sun--will be less in northern areas)= 480 watts. Assuming your panel is rated at 16.9 volts= 28.4 amps per day.Once you calculate your daily load the only other problems are finding room for the power sources, power storage and money to aquire. BOL,K

 

[Steve Dion]

Do you have an autopilot yet?

Ken:Do you have an autopilot yet. If not you may also want to consider a Simrad. Their WP10/30 consume .06amps on standby and .6amps in auto mode. The WP5000 is rated at 350ma.

 

[Ken Cobb]

Bottom Line

It sounds like one could use the auto pilot under normal cruising conditions without outrunning the power supplied by wind and sun, or with only some supplementing from the engine.This is an academic question to me, because on the inland lakes in the heartland we don't have occasion to use auto pilot at all. Hardly any boats around here even have it.