Breaker Amperage for Autopilot

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Originally Posted by donradcliffe

Yes, the autopilot will draw more than 20 amps. Not at the dock, but out in heavy weather, when you really want it to work.

You need a separate 30 amp breaker for the pilot alone, and at least 10 gauge wiring from the panel to the autopilot box.


How do I know this? I jerry rigged a Simrad pilot into a 70 ft race boat to bring it back from Hawaii. On the delivery to the Transpac start, I had it wired to an unused 20 amp breaker on the panel. It was an experiment and I had a crew of 7 so I was ready to take over steering if the 20 amps proved insufficient. It tripped going around Pt Conception, and we hand steered to quieter conditions. I installed the above breaker direct to the panel power feed wire in Hawaii and the pilot never tripped again.

i think he don't have 70ft race boat.
but for example

raymarine Type1 Linear drive will require 0.5A for the clutch operation and will draw a max of 15A when stalled, during 'normal' operation (typically, well balanced sail plan, a couple of degrees of weather helm), then 6-8 Amps continuous
really well-balanced sailplan is under 50W this is 4A

[donradcliffe]

The OP may not have a 70 ft race boat, but he has a Simrad system with hydraulic drive, probably a HLD2000. This is a bulletproof offshore unit rated at 1100 lbs peak thrust, and no comparison to the Raymarine Type 1 mechanical drive with its plastic gears and 650 lb peak thrust.

[smac999]

The pilot fuse is set to handle various pumps. Which pump you have and it’s draw may be much less. Some pilots are under 10a. The Garmin smart pump fuse is 40a.

It’s also possible the pilot runs through a relay. And the wire from the brraker is only triggering the pilot. Not powering it.

I often run a 20-30a breaker to a bluesea 5025 which then feeds all the nav gear. But the pilot is always done seperate for me. And often the vhf if enough breakers.