question

Until recently, SeeLevel N2K systems were a OEM product but you could request one from Garnet Instruments. I've been using one for several years now. I saw the 709-N2K system for sale on the Garnet web site so presumably this is now readily available to everyone.

Connection is via a CANbus interface which is built in to Cerbo and CCGX as well as others. If no built-in CANbus interface is provided, low cost USB CANbus adapters are available. For Raspberry PI, CANbus hats are also available.

Starting with v2.90, RV-C to a SeeLevel 709-RVC is possible. The main interface in Cerbo and CCGX can be set to RV-C, however if you have other N2K devices, a second or third CANbus interface is required and is supported in v2.90.

In the v2.90 release notes, it was mentioned that the SeeLevel RV-C systems don't report absolute tank capacity so these systems will only display a a percentage of tank capacity.

SeeLevel RV-C and N2K systems are limited to 3 tanks so if you have more than 3 tanks a second system would be required or alternates such as the Mopeka fresh water sensors would be required.

Hi zach-d,

1) Does the new Venus OS support the RV-C version (709-RVC-PM for example)?

Yes it does. No more need for the special 709-N2K. Do note that on the GX you have to choose the function of its VE.Can port. You can use it either for VE.Can/N2K. Or for RV-C. Which means that installing a Garnet Seelevel RV-C effectively makes it impossible to use that port to connect to a Victron device using VE.Can. Just like Kevin explained above.

Worded differently: If you are going to buy a Garnet Seelevel especially for connecting to the Victron system, then I'd recommend getting yourselves the Garnet Seelevel N2K model. This is from a technical point of view: I don't know if there is a price difference.

On the other hand, if your RV comes with a Garnet Seelevel RV-C module preinstalled, then you can consider hooking it up to the Cerbo - if indeed your VE.Can port is not yet used -, and change its configuration from its default (VE.Can/N2K) to RV-C.

2) If so, how does one wire this up to the Cerbo GX? Is it to one of the VE.Can connections (RJ45)? There are three wires on the SeeLevel for RVC (photo below). How would these get wired up to an RJ45 UTP cable?

Indeed it needs to be wired to the VE.Can port which is, RJ-45. Pinout is available in the datasheet.

Garnet Black (Ground) goes to Victron RJ-45 VE.Can pin 3
Garnet Blue (CAN Low) goes to Victron RJ-45 VE.Can pin 8
Garnet White (CAN High) goes to Victron RJ-45 VE.Can pin 7

See screenshots below for details. Note that not all RV-C pinouts are the same, and some Seelevel panels come with a connector for which I recommend you get a prewired contra with "flying leads" to prevent having to make/crimp such connector yourself.

We tested this ourselves, with a 709RVC-3856 (for which we had to make the mating connector).

Do note the one limitation: for the Garnet, tank levels shown on the Victron GX will be in percentage. Not actual volume in liters, gallons or another volume unit.

I’ll make sure we add information on how to connect a Garnet RV-C tank level sensor to the Cerbo user manual; thanks for asking!

Best regards, Matthijs

Thanks everyone, very helpful!

I think I will be best off with the N2K version of the SeeLevel but I am also now intrigued by the Mopeka option.

Is the wiring between the SeeLevel N2K and the VE.Can RJ-45 connection the same as it would be with the RV-C version?

Not answer, but more a relating question...
With regard to the SeeLevel sensors, I am a bit confused.

Seelevel's documentation indicates that these cannot be connected without the panel; however, if I read this correctly, if we connect using the VE.CanRJ45 connector, this IS possible. Is this correct?
2nd: how are 3 sensors connected with one RJ45 (newbie question, but I have not see this outlined).

3rd: on the Mopeka side, Where are these even available? when I searched, all I return is their LPG module.

1. Seelevel sensors all connect to the same (2) wires. BLUE=signal, BLK=ground

2. The back of display has (3) wires. RED=V+, BLK=ground, BLUE=signal

3. The back of N2K or RVC display has another connector for handoff to N2k or RVC network.

4. The job of the display is to convert the data from sensors (on BLUE wire) into meaningful data and both display it locally as well as hand that data off to the N2k or RVC network.

5. N2k or RVC displays are limited to 3 tanks. FRESH, BLACK and GREY. If you have (2) grays, like I do, you need to put a toggle switch to control which tank level is displayed as well as sent to N2k.

6. Garnet Industries is showing on their website their new "Soul" device. This does the same data conversion as the N2k and RVC displays but has 2 distinct differences.

a. Soul supports MANY more sensors and will send those out to RVC.

b. Soul does NOT have a display.

c. Soul is not available to us, just yet. Website clearly says "OEM ......."

In case it helps anyone else, I just replaced my SeeLevel 709-BTP3 with a 709-RVC PM to get the tank level information into my Cerbo GX. The wiring information from mvader along with the RJ45 pinout information in the Cerbo manual worked.

The feature information on the Garnet site and wiring diagrams there are really wrong and confusing though. I emailed them a few times and was told that the alarm output on my Bluetooth model wouldn’t work for the RVC model. However, the wiring harness that came with the RVC model was identical to the one from my Bluetooth model except it was missing the green LPG wire which makes sense. This doesn’t match the wiring diagram on the site (below), but it was great that the panel plugged right into my existing wiring and the alarm output worked fine. This also means there are no CANBUS/RVC connections on the main connector as indicated on the wiring diagram - the connector and harness match the Bluetooth model except for the green LPG wire.

There also isn’t a separate connector for the RVC interface as pictured in the diagram, but there are three wires soldered to the board there (ground, CANBUS+, and CANBUS-). So the installation was better and easier for me as I was able to retain my LED tank alarm and have the integration to Cerbo, but the diagrams and information from Garnet don’t indicate this.

Also, the pump switch is momentary on the RVC model for some ridiculous reason, but I was able to easily swap it out with the latched switch from my Bluetooth model. Garnet definitely needs to update their customer service training and website information…