NMEA network power

[Mikwallace]

I’m installing a NMEA 2000 network in the engine compartment. I would like to wire the NMEA power cable to the ignition system so when I start the port engine the NMEA power cable has power. Is there an ignition wire in the engine compartment that will meet this requirement? I don’t want to have to run a power wire from the ignition switch to the engine compartment.

Anyone done this?

[Hoplite808]

The NMEA 2000 network works through the backbone. You can connect the power part of the backbone up near the ignition if you want since you would have other parts to connect the chartplotters and such together there. Instead of closing the end of the backbone there connect a cable to the backbone in the engine compartment like you would need to anyways for the chartplotters to talk to the engine compartment bits.

N2K.png

[g36]

Much the same as the above diagram. On my 405 I installed mine this way. I have sensors etc in the engine room so I have baby backbone there. Then there's one cable from that to the helm there I have additional baby backbone that connects my 2 displays etc and there it gets power from under the helm. So no extra wire just the one network wire from the engine room. Dont forget to make sure you terminate the ends on the backbones

[Mikwallace]

As of now I do not have anything to connect to a NMEA network at the helm. Maybe in the future. Seems like an extremely difficult task to run the backbone to the helm if I don’t need it there. Where’s the tunnel to get from engine compartment to the helm?

I did find an unused connector on the rear of the starboard engine that’s hot when ignition is on, also when ignition is on and engine running. It’s a three wire connector with a termination dummy plugged into it. It has Orange, Yellow, & Black wires. The Yellow is the one I’ll use.

Here’s a picture of the wire:

IMG_4843.jpeg

Edit:

Is there a reason to NOT use that wire??

[bud37]

Source of the post As of now I do not have anything to connect to a NMEA network at the helm. Maybe in the future. Seems like an extremely difficult task to run the backbone to the helm if I don’t need it there. Where’s the tunnel to get from engine compartment to the helm?

I did find an unused connector on the rear of the starboard engine that’s hot when ignition is on, also when ignition is on and engine running. It’s a three wire connector with a termination dummy plugged into it. It has Orange, Yellow, & Black wires. The Yellow is the one I’ll use.

Here’s a picture of the wire:

IMG_4843.jpeg

Edit:

Is there a reason to NOT use that wire??

FWIW......Personally I would avoid connecting anything to the engine harness of a MEFI controlled engine that draws power and could cause interference but that is me being proactive and anal at best. That is my opinion only in this case, maybe someone knows for sure that it would be ok.

Question, what parameters are you monitoring from the engines and how do you see the data if it does not go to the helm area with the backbone?

[g36]

Mike.. eventually or whenever you get a display on the helm you'll want to connect it to the sensors etc in the engine room. You'll have some tees etc"(bacbone)" in there and nmea2000 cable run to the helm.there you can connect to some more tees,(back bone) and connect one of them to power which is readily available there under the fwd access panel behind the front seat and then also connect your display etc to the network there. Running from engine room to the helm is fairly easy I will look for my post I had helped another user on this forum with our same model and reference the path for you.

[g36]

May not be need this minute but Here's my instructions for wire path from engine room to helm on 405/406s....have run several on my 405 for nmea network etc. Stsrting in the engine room in the upper aft corner is the route youll take. Pull up the engine access aft on stbs side on the wall of the salon I have 3 compartment s. The bottom storage door has an access panel that you unscrew. The smaller vertical door beside t h at has a screws holding a panel also this will allow you to see the othe wires that run through this space. Then you'll nwed to remove the little piece that's velcroed in the corner by the window mine had the co monitor on it. Then go outside to fly and remove the screws that hold on the large vinyl trim piece lift it straight up it has hangers holding the top so don't pull it away from wall but lift it. Then unscrew the deck fittings in the side walls and you'll now have access to the wires it would be easiest here to snake a line down a use it as a pull wire to get your wire up to this point. Fyi leave a pull string in the route so if you need to pull anything else it will be much easier. the last part is to remove the screws holding the vinyl trim piece on the floor. The screws are hidden in the carpet in cubby above you can find them in the carpet or feel.to get access to the helm remove the front cushion let me know if you need help on that too. and I also ran a pull wire from there to the outside where you removed the trim panel. Easy peasy. Really it's not at all hard to do this so I may lost you along the way but let me know I'll help you out.....

Here's the post including this...viewtopic.php?f=10&t=3833&p=26430&hilit=Pull+wire#p26430

[Mikwallace]

FWIW......Personally I would avoid connecting anything to the engine harness of a MEFI controlled engine that draws power and could cause interference but that is me being proactive and anal at best. That is my opinion only in this case, maybe someone knows for sure that it would be ok.

Question, what parameters are you monitoring from the engines and how do you see the data if it does not go to the helm area with the backbone?[/quote]

On second thought, I tend to agree about tapping that yellow wire. I could put a waterproof relay on it and just use the yellow wire as a trigger and get the 12v from elsewhere?

I mostly want fuel flow info. The gateways I bought from Fox Marine provide much more info. Here’s a link to the gateways:

https://fox-marine.com/index.php?route= ... duct_id=50

The gateways will get power from the NMEA network and transmit data through that network to MFDs; and they are Bluetooth capable to transmit the data via Bluetooth to iPhone/iPad. Until I get MFDs I’ll use the Bluetooth and the app. However, they are powered by the NMEA network, so that’s why I’m doing a “Temp” network until I get MFDs.

[Mikwallace]

G36-

Thanks for that info. I about had it figured out except the part about removing the engine access floor on stdb side. I just now completed removing all the panels except the stdb engine access. I was wondering how to get around those steps down to the aft stateroom- and that’ll do it.

Thanks!

[Viper]

Source of the post.... I did find an unused connector....Is there a reason to NOT use that wire??

I wouldn't exactly call it an unused connector. It looks like the diagnostic plug to me. If that's the case, don't hook anything there. I wouldn't make the connection at the engine but if you insist on doing it there, find a spot that doesn't tap into the EFI side of things. You'll want a spot with continuous power while the ign. keep is in the ON position, something like the positive side of the coil for example. Having said that, I would want control of powering the network without having to turn the ign. key on. Having to power up the engine even without firing it to get some data or troubleshoot means you're powering your coil which isn't desirable without the engine running not to mention the alarm that will eventually sound in some models. For that reason, I'd prefer the power being switched at the helm independently of the engine. Eventually you may want accessories connected to your backbone and want them to work independently of engine operation, you won't be able to do that if you get your power off the engine only without turning the ign. key.

Take the time to do it right the first time so you're not doing it again or potentially causing another problem/gremlin that you may not think has anything to do with the NEMA hookup at your engine.