Autopilot power usage

  • Thread starter Alastair Longley-Cook
  • Start date
Status
Not open for further replies.
A

Alastair Longley-Cook

Even though my wife and I usually just go day sailing in our Catalina 30, I'm planning on having an autopilot installed to help when I go out solo and when my wife would pefer to just relax. The guy who would install it tells me I'd need an electrical system upgrade because the two batteries I have couldn't handle it - I couldn't run the autopilot for any length of time without running the engine. I'm wondering what experience others have had. Do autopilots like the Simad 3000 really use that much power when used for just relatively short periods of time on a day sail?
 
N

nick maggio

ST4000

I have ST4000 raymarine on my hunter 290 also have gps chartplotter vhf dept and speed am fm all on when I go day sailing with two deep cell batteries and never had a problem and I do single hand alot,the only time I ever had a problem was out on weekend over nighter and not because of autopilot ,we used too muuch lights and stereo at night plu all the electrnics during day time.
 
G

Gregg

Autopilot

Al - I have a Raymarine ST-4000+ on my H-290. The newer ST-4000+MKII would be more than enough to handle your boat. As for power usage, it draws about .06 amps in standby mode, and when it's engaged in auto mode, it draws about .8 amps. My house battery is a 100 amp/hr deep cycle battery (separate from the starting battery), and that's more than enough to run the auto pilot, speed, depth, and squelched VHF for quite some time. In *theory*, a top condition 100 amp/hr battery would power the engaged auto pilot alone for 125 hours. Add other loads (nav lights, interior lights, stereo) and your consumption goes up. But as long as your house battery has a decent capacity and is in good shape, you should have no problem running the basics (a/p, spd/depth/ nav lights)for a day or evening sail.
 
D

Don Alexander

Suggestion

Alastair, If your installer knows so little about autopilots may I suggest you find another guy.
 
P

paul arceneaux

autopilot

just installed st4000mk11 on my 28.5 myself job was fairly easy to do just had to squeeze in some tight spots to run the wires. works great and i only have two gel batteries. paul slipaway
 
N

Nick

Auto-Pilot . . .

Get yourself a new Gel Cell House battery, if your not sure about the old one. Make sure your two bank system is truly isolated from each another. And get a new mechanic . . . Nick "Julia Bell" C-27, #86
 
J

Jack

I've sailed overnight

with a tiller pilot, running lights, compass light, and GPS on a standard car battery (60AH) and started the engine (12hp Yanmar single) with that battery the next morning. I had a second battery but never switched to it. Either your mechanic has very limited knowledge or he is trying to run up your bill. In either case, you need a new mechanic.
 
Feb 26, 2004
23,129
Catalina 34 224 Maple Bay, BC, Canada
Energy Budget

Alastair To fully answer your question, you should consider making up an energy budget. All the rest of the answers don't answer your question. We don't know if you have lots of DC-hungry critters on board, how long a "daysail" is to you (8 a.m. to 8 p.m., or noon to four) or how big a house bank of batteries you have. Just saying "I have two gel cells" doesn't say how big they are. I suggest you go to the West Marine website and check out their Advisors, which explain how to size you battery banks and what the running load for most appliances are, do the budget based on how you use your boat, and that way you'll feel comfortable with what you have. There are many other energy budget descriptions in other references, like Calder's. Good luck, Stu
 
Status
Not open for further replies.