Boat Monitoring / Electrical Question

[FlyMeAway]

We're thinking of putting boat monitoring (a Vesper Cortex, so we also upgrade to full AIS) on board. The Cortex has a built-in functionality for battery monitoring and any NMEA2K sensors.

I'm trying to decide how to wire the thing and would welcome input on the three options I'm considering.

Option 1: Wire directly to the "always on" engine fuse block.
Pros: Can monitor shore shore power (through charging voltage on engine battery) as well as boat position while still keeping house bank off. This could be helpful for leaving the boat at the dock over winter while still running AC loads (heaters).
Cons: Could run engine battery down accidentally. Requires a separate sensor and install to monitor voltage on house batteries; that sensor will be NMEA2K so will only work when the NMEA backbone has power. Likely a more expensive install even without second sensor (have to run new cables from helm to engine battery).

Option 2: Wire to a spare fuse behind the helm
Pros: Cheapest install. Will monitor house battery voltage directly.
Cons: Turns off when house batteries are off.

Option 3: Wire to house batteries directly
Pros: Best of options 1 and 2 above
Cons: Most expensive/complex install (I think) as it will require a new "always on" fuse block for house batteries


Also, two side questions:
1) Does Garmin output house battery voltage over NMEA2K?
2) Where is the NMEA2K backbone powered from? (on a 2018 R-31CB)

 

[Kevin Lamont]

We're thinking of putting boat monitoring (a Vesper Cortex, so we also upgrade to full AIS) on board. The Cortex has a built-in functionality for battery monitoring and any NMEA2K sensors.

I'm trying to decide how to wire the thing and would welcome input on the three options I'm considering.

Option 1: Wire directly to the "always on" engine fuse block.
Pros: Can monitor shore shore power (through charging voltage on engine battery) as well as boat position while still keeping house bank off. This could be helpful for leaving the boat at the dock over winter while still running AC loads (heaters).
Cons: Could run engine battery down accidentally. Requires a separate sensor and install to monitor voltage on house batteries; that sensor will be NMEA2K so will only work when the NMEA backbone has power. Likely a more expensive install even without second sensor (have to run new cables from helm to engine battery).

Option 2: Wire to a spare fuse behind the helm
Pros: Cheapest install. Will monitor house battery voltage directly.
Cons: Turns off when house batteries are off.

Option 3: Wire to house batteries directly
Pros: Best of options 1 and 2 above
Cons: Most expensive/complex install (I think) as it will require a new "always on" fuse block for house batteries


Also, two side questions:
1) Does Garmin output house battery voltage over NMEA2K?
2) Where is the NMEA2K backbone powered from? (on a 2018 R-31CB)

Hello,

All good options but just depends on your preference, adding a fuse block isn't as difficult as you think just depends on where you would like the fuse block located. The Garmin also only displays the house and engine voltage, the NMEA2K backbone is located behind the galley fridge. Hope this helps.

Thanks,

 

[FlyMeAway]

Thanks Kevin! To follow-up, I know the location of the NMEA backbone but wondering where it actually gets power (e.g., does it have its own power supply or does it get power from the Garmin?). I'm guessing from the plotter or the VHF as it does not have it's own fuse. Does that mean the plotter or VHF has to be on to power the backbone?

Also, where does the Garmin get battery voltage from? Does it sense it directly from the battery? And does it send that voltage out over NMEA for other NMEA displays?

 

[it4llc]

The Garmin also only displays the house and engine voltage

We've got a 2020 C28 and it only seems to display the house bank on the Garmin. Should we also be able to get the engine voltage, and if so, where should I start looking? Thx.

 

[Kevin Lamont]

Thanks Kevin! To follow-up, I know the location of the NMEA backbone but wondering where it actually gets power (e.g., does it have its own power supply or does it get power from the Garmin?). I'm guessing from the plotter or the VHF as it does not have it's own fuse. Does that mean the plotter or VHF has to be on to power the backbone?

Also, where does the Garmin get battery voltage from? Does it sense it directly from the battery? And does it send that voltage out over NMEA for other NMEA displays?

The backbone gets is power via a yellow cable going from the fuse block to the backbone, the plotter then gets its power from the backbone. The backbone is powered once the house power is on, the VHF is fused at the fuse block. Fuse diagrams are available under the owners manual in the "Factory Technical Bulletins"

The Garmin displays the voltage it is sensing from the backbone, it is not direct from the batteries. Best volt meter is at the AC/DC panel depending on the model boat, smaller boats are not equipped with a volt meter. Hope this helps.

Thanks,

 

[Kevin Lamont]

The Garmin also only displays the house and engine voltage

We've got a 2020 C28 and it only seems to display the house bank on the Garmin. Should we also be able to get the engine voltage, and if so, where should I start looking? Thx.

Yes the Garmin plotter does display engine voltage, this would be under the engines tab under AV, gauges and controls. Also you can set this a a tile on any of the navigation, sonar, radar etc screens. You press and hold on a tile till the menu shows up and then you can change it to whatever you would like. Hope this helps.

Thanks,

 

[FlyMeAway]

The backbone gets is power via a yellow cable going from the fuse block to the backbone, the plotter then gets its power from the backbone. The backbone is powered once the house power is on, the VHF is fused at the fuse block. Fuse diagrams are available under the owners manual in the "Factory Technical Bulletins"

Thanks! I realized that the R-31 owners manual (v7) doesn't list the NMEA backbone or plotter in the wiring schematic section. The VHF is listed (bottom of page 30) but not the NMEA. I'm seeing now that it is list on the dash fuse block diagram (p. 10) -- I was using the p. 30 diagram as the master, but seems like I should focus on the fuse block on p. 10 which has a lot that isn't on the p. 30 diagram.

Does the plotter really get power from the backbone? I was led to believe that the backbone doesn't typically have enough power for large devices like that. What is the "GPS Display" fuse for, then? Thanks!

 

[it4llc]

Yes the Garmin plotter does display engine voltage, this would be under the engines tab under AV, gauges and controls. Also you can set this a a tile on any of the navigation, sonar, radar etc screens. You press and hold on a tile till the menu shows up and then you can change it to whatever you would like. Hope this helps.

Thanks,

Thanks Kevin. I realized that part of the issue in it not working is the sequence in which I turn on the devices. If I turn on my 8612, and then turn on the ignition, I can get the engine voltage. However, if I wait too long to turn on the ignition, the engine voltage (and and other engine info) don't seem to register. When we anchor, and I turn off the engine and then turn it back on, the engine info also doesn't register unless I turn off the 8612, then restart, and then turn on the ignition. At least now I know what to do so all good.