Mystery Item

[Rimica]

Does anybody knows what this is? It's functions?
It is installed between the charger and the autopilot. Charger goes to it and auto pilot from it.

[marc2012]

It is a solonoid.purpose there ?

[cal40john]

The two big wires are connected together when you apply power to the two little wires. Need a better description of which wires go to what.

John

[GordMay]

The two small terminals are a switching circuit, energising the coil; which in turn closes the circuit between the two larger terminals, allowing a larger load to run.

➥ http://www.cruisersforum.com/gallery...r&imageuser=79

➥ http://www.colehersee.com/pdf/H-Relays.pdf

[S/V_Surya]

It is a relay. I have one for my windlass. It for switching large power loads. When I turn on my windlass which takes a large current it activates the relay and thus powers the larger load. Small wires turn on the relay coil and closes contacts on large wires.

[sailvayu]

Like John said it is basically a switch that is turned on and off by applying power to the small terminals. They are often used for switching higher currant carrying conductors that would require a big switch if done manually. I am thinking you traced the wires wrong as it is not likely connecting the charger to the autopilot, just does not make any sense there. I would check again.

Good Luck

[GordMay]

Originally Posted by sailvayu

... I am thinking you traced the wires wrong as it is not likely connecting the charger to the autopilot, just does not make any sense there. I would check again.
Good Luck

As everyone says, or implies.
Check again.

[Sailmonkey]

What type of auto pilot? Hydraulic ram, linear electric ram.......
We all need to know more....

[Rimica]

Attached is the diagramme of the connections

The 2 big wires go to the house batteries
The 2 small ones go to unknown destinations

There are no descriptions on the mystery item (serial, make, manufacturer or specifications).

A relay/solenoid makes sense but how do you spec a replacement part for this?


Thank you to all

[Rimica]

Forgot to add the Autopilot mentionned is the "SmartPilot" computer box

[sailvayu]

Cole Hersee PN 24117-01BP It is used to reduce the size of the power switch for the autopilot. Help reduce voltage drop to the autopilot from wire runs as well. Hope this helps

Fair Winds

[Beausoleil]

Originally Posted by sailvayu

Cole Hersee PN 24117-01BP It is used to reduce the size of the power switch for the autopilot. Help reduce voltage drop to the autopilot from wire runs as well. Hope this helps

Fair Winds

Expanding on what sailvayu said:

I'm not sure which SmartPilot you have, but we have the S3G model from Raymarine. It has an input for a remote switch, which accomplishes your setup without needing the external relay.

What your external relay accomplishes is reducing the length of the run of the heavy high-current carrying cables supplying the autopilot - enabling you to use lighter-gauge cable. For example, let's say the distance from your autopilot to your breaker panel was 25 feet, the distance to your house battery bank is only 5 feet, and your autopilot calls for 25 amps. Allowing for 3% voltgage drop and cable rated at 105 degrees C , if your SmartPilot needs 25A, then you'd need a minimum of #4AWG cable back to the breaker panel - and that's not even taking into account the existing cable run supplying the breaker panel itself from the battery bank. Since you really need to also account for the total cable run - from the autopilot to the breaker panel switch, and from the panel to batteries, you would probably need at least a #2AWG cable and possibly more, and worse - you may actually exceed the safe current-carrying capacity of that panel supply cable and need to replace it with larger cables.

Instead, if you use the remote relay, then you'd only need #10AWG cable to make the 5 foot run and back to the battery bank. If the solenoid's energizing coil only needs 5A, then long run back to the breaker panel could safely use 18AWG cable, and you'd only need a 5A breaker, not a more expensive 25A breaker.

There are three minor drawbacks to think about: (1) the relay uses some battery power, so in the overall scheme of things one would have to consider that in power budget planning, (2) there's one more item that could possibly fail, but most importantly (3) the heavy cable from the autopilot/relay to the battery bank should be protected by a fuse - not just connected directly to the battery bank.

Sometimes, there's just no easy way to run long lengths of heavy-gauge cable, so you have to compromise a little. That's apparently what the previous owner of your boat decided to do.