Is it acceptable to bypass battery isolator switch?

[Elessar]

It's definitely not the way I wire my boats. With two exceptions, automatic bilge pump and permanent wire to the FM radio, off means off. Some people have the VHF permanently live although I can never see the logic in that. Definitely not the autopilot IMHO. You would never want it on its own anyway. The only possible reason might be high current draw necessitating direct connection to the battery but there are plenty of alternatives to that.

Agreed with 1 addition. The eberspacher. So I have the main breaker which is 2 pole. It cuts off the engine and domestic batteries. Next to it i have a breaker for the permenant supplies, which are bilge pump float switches x3, radio memories, eberspacher and inverter. Why the eber? Because its bad for it not to go through the cool down cycle. But I can see no reason at all for the autopilot not to be through the main breaker.

 

[davidpbo]

This thread has got me thinking about what I need to do with my battery box.

Small boat. I have one 80ampere hr battery and currently no high current devices like starter motors.

Is it good practice to have fuses or switches in the battery box or should they be outside it?

I am thinking if the batteries gas.

 

[VicS]

This thread has got me thinking about what I need to do with my battery box.

Small boat. I have one 80ampere hr battery and currently no high current devices like starter motors.

Is it good practice to have fuses or switches in the battery box or should they be outside it?

I am thinking if the batteries gas.

My preference would be for a main fuse and isolator immediately outside the battery box, the fuse being rated to protect the wiring between there and the main switch/fuse panel.
You could use an isolating battery connector

In reality my battery is not in a box, I have easily detachable battery connectors ( croc clips), and 35yrs down the line the main fuse is still on the list of round tuits

 

[lpdsn]

When I fitted my new autopilot I wired it through the fuse box and switch panel at the chart table. Previous one was powered on whenever the isolator switch was on and I preferred to be able to turn it off.

I used 6mm2 cable and calculated the voltage drop for 25A. I chose 25A for the calculation as that's the size of the fuse the autopilot instructions specified.

So my view is it shouldn't be wired directly. Just make sure your cables (for the complete circuit) will avoid too much voltage drop.