Relay for Autopilot Pump

[smac999]

You din’t Really want a relay On a pilot motor. The pilot will change its output voltage to control the speed of the rudder change.

If you are running relays. The only choice becomes full speed rudder movment.

Mount the pilot controller between batteries and ram. Use a relay on input side of pilot computer. If you want to be able to shut off from dc panel.

[SailRedemption]

Originally Posted by smac999

You din’t Really want a relay On a pilot motor. The pilot will change its output voltage to control the speed of the rudder change.

If you are running relays. The only choice becomes full speed rudder movment.

Mount the pilot controller between batteries and ram. Use a relay on input side of pilot computer. If you want to be able to shut off from dc panel.

Thanks, that's what I meant to say (see my post above)! I am clueless why I said pump not the whole system. Yes, I'm looking for the best relay to switch on the control unit.

[Moontide]

Guess I may be missing something here.



One way or the other you are going to need the high amp capacity wiring to run the pump. Where is that coming from if not the panel? If you locate the AP brain somewhere in line between the panel and the pump then you could run smaller wires up to the control head. On my boats the brain has always been fairly close to the pump with a fairly long run from the brain to the helm/control head.



Assuming the pump is a reversing motor, I think most AP's have built in relays so the question is moot if you wire panel-AP-pump. The wire to the AP and on to the pump must be rated to carry the pump load. (The AP itself uses very little juice)

[RaymondR]

With a long run of wiring and supplying all the power for the autopilot there is no way to get around the need for high amp capacity wiring. You need to supply the motor which is going to draw a lot more power than the electronics and if the wiring is too small and there is a large voltage drop the electronics will drop out.

[SailRedemption]

As I posted before, I don't need a relay for the pump as the autopilot controller will power the pump. I was asking for recommendations on a relay to supply the power to the controller since the length f run from panel is 3 times that to the battery. I could run smaller wire to switch the relay.

[RaymondR]

Originally Posted by SailRedemption

As I posted before, I don't need a relay for the pump as the autopilot controller will power the pump. I was asking for recommendations on a relay to supply the power to the controller since the length f run from panel is 3 times that to the battery. I could run smaller wire to switch the relay.

So what you could have is a short run from battery to the autopilot because they are close but because the supply is to be switched at the DC switch panel which is a relatively long way away you would like to use a relay in the short run.

Fair enough. Since the relay will only be switched on and off say once a day any fairly high current relay will do the job. The large auto relays with spade terminals will comfortably handle 30 or more amps and will do the job however the coils in them pull a couple of hundred milliamps. A solid state relay will also work and only pull a few milliamps.

[SailRedemption]

Thanks all, I ordered a couple of the uxcell ssr from Amazon.