Installing Simrad NSX/SmartCraft and transducer; 2004 Sunesta 252

[LAKETIME]

I had Boat Outfitters use Starboard to fabricate five pieces that I will assemble. They will be able to router all the edges that I requested.
I will use the existing cupholders to stabilize a 4" x 12" platform that will support the gimbal bracket that supports the Simrad unit. This is a provisional measure that I'll use for now, till I can decide on a fabricator to help me with the ultimate project that I'd like to start sometime in the future...

 

[LAKETIME]

Just a little update...
I've installed the NMEA 2K backbone, connected the Simrad to it, but haven't installed the power or the Lowrance sonar (transducer) yet.
A post that I read in another forum brought to my attention what I think would be worth considering...

"Many boats are rigged with the NMEA-2000 network power controlled by the engine ignition key switch. That method works if you never want to use the network when the engines are not running. Modern engines have expensive computer controllers, and switching the ignition key to ON just to get power to the network will also put power to those computers. The computers are really expensive, and it seems a bit odd to operate what might be a $2,000 computer to just provide power to a network when the engine is not running.

A better solution is to let the network be powered by either the ignition key switch for the engine (or engines), and also by a dedicated toggle switch. With that option you can have the network operating without needing to run the engines or put time on their computers.

Generally if you get power from the ignition key switch that power will be coming from the engine cranking battery. If there is a voltage sag at engine start, the network could be affected. For that reason I think it better to power the NMEA-2000 network from an isolated battery--a HOUSE battery not used for engine cranking except in emergency.

On my boat--which might be a bit obsessive--I use a relay to provide HOUSE battery power to the network. The relay coil is operated by the output of two steering diodes, one getting power from the ignition key switch (so the network power comes on automatically with engine running) and the other getting power from a dedicated toggle switch."

So...can anyone tell me how to find the separate battery leads that could be found in the helm? As you can imagine, there are numerous wiring looms and harnesses in that area.
My goal would be to use one of my two batteries for the NMEA 2K-related electronics, etc.; and one of them for engine ignition, etc.

2004 Chaparral Sunesta 252/Mercruiser Mag 350/Bravo 3

Thanks in advance,
Dan

 

[Iwantachaparral]

You probably have a spare circuit breaker under the dash that you could use for power.

 

[Iggy]

It's not a bad thing to use a specific switch to turn on the NEMA network. More so when the boat is not in use. Other wise it could be a drain on the batteries depending on what is on the network.

 

[LAKETIME]

Another update...
I looked around the helm instrument cluster and noticed that there is a switch to the very right of the steering wheel that is labeled 'wipers'. Since I don't have wipers, I was wondering if anyone had any ideas about how to dedicate this switch to all the electronics (Simrad, stereo, VHF radio, etc.) on the boat that are not already on switches. When I did a quick look underneath that panel, I noticed that there are wires connected to it, but I can't imagine where they would lead. I'll remove the panel to get a closer look...

 

[Iggy]

Go to the back of that switch for power.

 

[LAKETIME]

Yet, another update,

I removed the panel, which contained several switches, one of which said 'Wipers', which I assume is not being used, since I have no wipers.
The first image is the back of the panel.
I noticed that there are wires attached to it, some of which (purple and yellow) seem to be shared with the rest of the switches on this panel.
The second image shows the back of the switch itself, where the various colors of wires are connected.
-the two yellow wires are connected together, then are plugged into the pin on the back of the switch.
-the yellow and the purple wires are shared with all of the switches.
Would someone be able to know if the yellow and purple wires could be power and ground wires?
If I were to use this switch to power the accessories (radio, Simrad, stereo, etc.), which wires would I use? Would it be one of the black on orange or red on orange wires???

Thanks in advance,
Dan

 

[Iggy]

On boats, ABYC standard is that yellow is negative. Not knowing your boat, I would say that these switches light up.

So you need to use a meter and find the load side of the switch.

 

[LAKETIME]

One more power source, however, not switched...
I am considering the accessories outlet, which is where I usually plug in my phone charger, conveniently located to the left of the steering wheel. There are two yellow and one red wire:

 

[Denny]

Star Board is neat stuff, it comes in black or white, and different thicknesses. Starting at 1/8 " I believe.