Isolator switches

[dave1985]

I bought a 1985 36 convertible a couple months back and was looking for help with something new to me. Unlike the "1/2/BOTH/OFF" battery switches on my previous boats, the Hatteras has isolation switches. With the battery switch, it was pretty clear that you could shut both off while away, combine the two to charge underway or choose one as a house battery when not. I realize the isolation switches can be used to switch one or both of the banks off as well as the generator and DC serivce. In a scenario where one would be away from the boat and want to shut things down or a battery went bad and you want to protect the other, the on/off switch makes perfect sense. Short of that, is there something I'm missing about the function of these switches? Thanks for the help.

Dave

 

[SKYCHENEY]

In most Hatteras systems, you have two banks. Usually one battery bank is dedicated to starting one engine and the generator. The other battery bank is dedicated to the other engine and the house loads. Each bank has an aluminum box on the bulkhead. In that box are the battery disconnects as well has some fuses. The fused lines are not run through the disconnect. Those are separate. So, when you turn off the engine disconnects, the generator disconnect and the house disconnect, you will still be powering your bilge pumps and systems monitor. Also, your charger will still charge the batteries if the disconnects are set to the off position.

The advantages of this setup are that you should always be able to start your engines, even if the house bank goes too low. Most of these boats have a parallel switch at the helm to aide in starting when you have a bad/low bank. Those parallel solenoids are also housed in that aluminum box. If you are leaving the boat and do not need to run any house loads from the batteries, then switch off the disconnects. You will still have power to the bilge pumps. You can also switch off the engine and generator disconnects. This may keep someone from starting the boat if they were to break in.

 

[Maynard Rupp]

Ours is an "86 36 convertable so we have the identical setup. I never switch any of those off. I have to test them, but never in practice. At the marina in Miami the boat is always plugged in and has one AC unit running. When we were in Detroit, the inside winter storage marina required actual disconnecting of all batteries, so we disconnected the positive terminal lead on both of our 8D batteries, but never rotated the switches.

 

[fissioneng]

In my 86 MY, the bilge pumps are fed from the Ship's Service panel which is fed from the Ship's Service disconnect (to the port bank) in between the big engine disconnects. If you switch the Ship's Service disconnect off, the bilge pumps won't work.

 

[SKYCHENEY]

If you don't have the wiring diagrams for your particular boat, I highly recommend buying them from Hatteras since it looks like many models/years have differing configurations. As they say YMMV

 

[fissioneng]

I certainly agree with Sky. I recently purchased my drawings because they weren't with the owner's manual when I bought the boat.

I find it odd that the bilge pumps aren't wired independently of the main DC panel. It sounds like they are on some boats. My old Trojan had independent circuits so you could turn off power to everything except the bilge pumps.