NMEA-2000 Backbone Power On-Off Switch

Electrical and electronic topics for small boats
Jefecinco
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NMEA-2000 Backbone Power On-Off Switch

Postby Jefecinco » Sat Aug 17, 2019 3:57 pm

I recently read it's advisable to install an on-off switch in [the NMEA-2000 network power circuit] to prevent slowly discharging the batteries during storage. However, if the battery switch is in the OFF position, would the [network power circuit] switch be redundant?
Butch

jimh
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Re: NMEA-2000 Backbone Power On-Off Switch

Postby jimh » Sat Aug 17, 2019 4:30 pm

If the branch circuit that supplies power to the NMEA-2000 network loses power when the battery which is in the OFF position, then the network will be de-energized.

Generally there is a method provided in a NMEA-2000 network to control network power by some other means than to cut off all 12-Volt DC power to the boat from the boat battery. Having a switch that only controls the network power is the usual method. I would NOT consider that having a switch in that circuit is redundant.

Nota Bene: the network being discussed is a NMEA network. It is not a NEMA network. Many devices related to electrical power are qualified by NEMA, but generally not for use on recreational boats. NMEA and NEMA should not be confused or their names intermixed. The two organizations are quite separate and distinct from each other.

Jefecinco
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Joined: Fri Oct 09, 2015 6:35 pm
Location: Gulf Shores, AL

Re: NMEA-2000 Backbone Power On-Off Switch

Postby Jefecinco » Sat Aug 17, 2019 4:51 pm

After only a little thought I realized the question was not well thought out. If a network is powered by a direct connection to the battery, turning the battery switch off would not de-energize the network. I'm sure many networks, like bilge pumps are connected directly to the battery.

I read an old post by BlueWaterPirate (BWP) in which he included photographs of his network switch.
Butch

conch
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Re: NMEA-2000 Backbone Power On-Off Switch

Postby conch » Sun Aug 18, 2019 9:24 am

Butch, a bilge pump connected directly to the battery has another switch of some type somewhere to act upon the presence of water or it would run all the time.

I like a separate switch for the NMEA-2000 system to be able to reboot or work on the system. This way the MFD,s or other items on the backbone will stay powered on.
Chuck

Jefecinco
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Re: NMEA-2000 Backbone Power On-Off Switch

Postby Jefecinco » Sun Aug 18, 2019 10:43 am

Chuck - Thanks. I've decided to install a power switch for the network. I'll probably install the switch just inside the console door on the aft console face for quick easy access.
Butch

Simon
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Re: NMEA-2000 Backbone Power On-Off Switch

Postby Simon » Mon Sep 02, 2019 8:22 pm

I just ordered a Lowrance NMEA 2000 starter kit from West Marine for $55 and a Yamaha engine interface 120-37 cable on Amazon. I plan to add an on/off switch as described above. Thanks for this thread, I didn't even think about a switch to power down the backbone.

Simon
1987 15' Sport CC