Move NG 12v power from AP circuit.

[Kshaw]

Hello, everyone. This is my first post, so thanks in advance for any and all help.

My issue is with 12v power supplied to my SeatalkNg bus. Currently it comes from the Autopilot via a SeatalkNg spur cable. This means I must run the autopilot whenever I want to use instruments on the SeatalkNg bus. My AP and instruments are on separate 12v circuits, so I should be able to power the Ng bus even when I don’t use the AP.

I’m considering cutting the 12v wire from the AP Ng spur cable, and then reintroduce 12v onto the Ng bus from the instrument circuit via an Ng power spur cable.

First, does this sound like it will work? Second, Does anyone have another suggestion that does not require me to dissect an Ng spur cable?

Thanks again!

[Pete7]

Yes it should, but I am surprised that the power comes via the AP. Normally the power cable is supplied with Seatalk NG kits. Are you sure the Seatalk NG doesn't supply power to the AP which the smaller Evo 100 APs do. Or did someone use the AP main switch to also power the network somewhere else perhaps?

Pete

[Kshaw]

Thanks for your reply, Pete.

Yes, I’m certain. I installed the AP myself, and stood up the Ng bus since all of our existing navionics are Seatalk1 and 183. The AP installation instructions show the Ng bus powered by the AP, and I’m sure that is the case since I tried moving my wind display to the Ng bus, and it only worked when I powered up the autopilot.

For now I moved everything except the AP back to the Seatalk1 bus and it all works, but I want to install a depth sensor that talks N2k, so I need to solve the power problem.

Again, thanks Pete.

Kshaw

[Statistical]

That is a very unusual configuration and has the very obvious problem you have encounrted. Raymarine doesn't do that anymore if they did at one time

"The ACU-100 and ACU-150 do NOT provide power
to the SeaTalkng® backbone. The backbone
requires a separate 12 V dc power supply"

https://www.raymarine.com/uploadedFi...utionSetup.pdf

I would imagine you could cut the 12V line on the NG branch wire to the AP without issue and install a separate power branch line to the NG backbone. The configuration is just really unusual so probably not going to know for sure without trying.

[Kshaw]

Thanks Pete, Statistical.

Just to be sure, I reviewed the tech manual. While the 100 and 150 show external power to the Ng bus, the 200, 300 and 400 show the bus powered from the ACU. We have a 400.

I hate to destroy a spur cable, but it looks like the only alternative is to give it a try.

Thanks for the assist.

[Statistical]

Originally Posted by Kshaw

Thanks Pete, Statistical.

Just to be sure, I reviewed the tech manual. While the 100 and 150 show external power to the Ng bus, the 200, 300 and 400 show the bus powered from the ACU. We have a 400.

I hate to destroy a spur cable, but it looks like the only alternative is to give it a try.

Thanks for the assist.

Before you cut the branch cable ....

It looks like there is a seperate fuse in the ACU-400 for powering the NG bus independent of the fuse for the ACU itself.

" 2 SeaTalkng® fuse (fuse power supply from ACUto SeaTalkng® backbone)"
pg 29
https://www.manualslib.com/manual/15...page=29#manual

Worth a shot to pull that fuse. It looks like it should prevent power from the ACU to the NG network. Once you verify that works you can install a separate power branch for the NG network. If it doesn't work you could always just cut the branch power leads.

Still I am going to say really weird design decision on the part of Raymarine.

[Kshaw]

Thanks, Statistical. I agree it is a strange design decision.

I will certainly give the fuse a try before I start cutting cables.

Thanks again.

[smac999]

I don’t understand the destroy part. Just buy a stng power cable. And connect the bus to new power where ever you want.

https://www.ebay.com/itm/RAYMARINE-A...-/174427836722



As for the pilot it will have a switch and or fuse to shut off power to the stng bus.

[Lasseman]

Raymarine owner here, just my 2cents after installing and using same setup (and my first post here).

Raymarine uses 12v clutch on their Mechanical linear drives and Mechanical rotary drives. Even on 24v drives. This means the actuator control unit "ACU" needs to have a DC to DC converter built in for the clutch.

My assumption is that during the product design some engineer came up with an idea to reuse the clutch DC to DC converter for the option of powering the NG/N2K bus. This optional NG/N2K bus power supply can be enabled/disabled by a small switch above the NG connector, no need to pull any fuse or cut any cables...

I have a 24v boat and i use this option. 10000NM two atlantic crossings so far all ok, 50foot sloop. For a 12v boat i dont know if i should have used it as primary NG/N2K power source, but certanly as an backup.

Raymarine even give an option to put the ACU unit to "sleep" while still enable the DC to DC bulit in converter, check the manual. I did try this, but could not see any difference in on power consumtion on my 24v bus if i enable the ACUs "sleep" function. Only thing i noticed was that the ACU stopped sending out rudder position on the NG/N2k bus while in sleep mode.

So think of it as an free/optional 24v to 12v DC to DC converter for ur NG/N2K bus.

[Frankly]

You do realize if you are not powering the AP motor (ie standby) the power draw of the AP is minimal.

Because I was one spur port short I just jumped a 3 A in line fuse connection from the 12V feed on the ACU 100 over to the 12V STNG connection on the AP. You could just reverse the process with a switch. Never could figure the games (other than $$) RM plays. The old X-5 actually has the pads on the printed circuit for a fuse to power the NG bus RM just did not bother to install the fuse clips/ fuse.


Frankly

[James M B]

Seatalk cables are readily available at defender.com so you could replace one that you cut if needed.

[Lasseman]

Dont know if you responded to me but, the AP "Autopilot" is the EV1.
From Raymarine: "The innovative EV1 sensor core combines advanced solid-state sensors with the Evolution autopilot processor into a single easy-to-install housing."

EV1 AP uses max 30ma (N2K Len 1) and its power comes from the NG/N2K bus. You can not unpower the AP without disconnecting it physically from the NG/N2K bus. Why would you?

If you talk about the actuator control unit ACU that powers the rudder drive motor, it (ACU) can be power dissconnected completly by a breaker without any feature loss (except from rudder position on the NG/N2K bus and driving the rudder motor of cource).

So
* ACU power supplied but autopilot in standby
* ACU breaker dissconnected
* ACU in "sleep mode"

Those three had no difference in the boats power consumption for me. I tested this with ACU model 400 on 24v, and ACU change in power consumtion was non recogniced on my 24v Victron shunt monitor.

[Frankly]

Assuming the 12 Volts is originating from a common power source (12 V return in particular) would expect most configurations to work electrically. The one point might BUITB is that if your ACU does power the NG network directly and that source is not isolated (diode/ dc dc converter including the 12V return) then the 12V might back feed through a low current trace to the actuator drive circuit and burn a trace due to the substantial motor current if you punch auto by mistake. Not a make your day experience. My guess is that RM probably anticipated that or the network fuse would blow, but if you power up the NG network and the display comes up be careful.


Frankly

[Pete7]

Originally Posted by Kshaw

I hate to destroy a spur cable, but it looks like the only alternative is to give it a try. Thanks for the assist.

Well, you have some options, but if you do have to split a cable its not the end of the world. Indeed I had to do this when connecting the ST60s to Seatalk NG. The live feed in the yellow black cable needs fishing out, cutting and isolating so that the ST60s are powered by their own supply and the NG Network is also supplied by its own supply. This isn't in the manual btw, but later advice from their support forum.

Pete