Scheiber watertank level to Cerbo (via GX-Tank)

[tjurd]

Hi all,

Would love some advice from the electrical guys.\

Situation:
Boat: 2010 SO 42i
Specific: Scheiber panel 
See attachment for scheiber panel layout.

Panel is used for among other monitoring water tank level. Tank level shows when pressing tank button:
- Pressing once activates wire JE1 sending power to a control box for the Aft water tank, Scheiber panel receives a voltage in return through wire JE.
- Pressing twice activates wire JE2 sending power to a control box for the forward water tank, Scheiber panel receives a voltage in return through wire JE

What I want:
I am installing a Victron Cerbo + GX-Tank (GX-Tank is needed to display water tank levels from this rare type of level system the sheiber panel uses).
I want to be able to view water tank levels on Sheiber panel as wel as monitor through Victron Cerbo. (on MFD etc.)

To be able to read water tank levels through the Victron Cerbo the control boxes at the watertanks need constant power through JE1 and JE2. 
Doing this I expect wil confuse the Scheiber panel and give two readings/ faulty readings.

Plan:

Connect JE1 to a dedicated Relay
Connect JE2 to a dedicated Relay

In normal mode, Both relays will route 12v to both control boxes but not be connected to JE1 and JE2 from the Scheiber panel. Thus both tanks sending a signal to the GX-Tank.
- Pressing water tank button on Scheiber panel once will activate relay for JE1, connecting the the control box from the aft tank to the Scheiber panel. (but not disconnecting the GX-Tank and 12v wire)
- Pressing water tank button on Scheiber panel Twice will activate relay for JE2, connecting the the control box from the forward tank to the Scheiber panel. (but not disconnecting the GX-Tank and 12v wire)

Questions:
1) Is this possible? Or wil I break something?

2) Is there and easier way?

3) any relay or control board or so you would advise?

Thanks!

Regards from SV Ayana 

[virtualburton]

I did exactly this on my 469, but I did it using CZone…

There are a number of systems that can take the analogue voltage inputs from the Jeanneau Scheiber sender. They put out a voltage based on the tank level at 0, 25, 50, 75 and 100%. If you search through my older posts, you’ll find where I did this on my boat and there’s a lot of information in there including the voltages to use to calibrate.

Caveat! Below is based on my understanding, and your mileage may vary!

I know on the Cerbo GX you can configure up to four tank inputs directly, but only resistive senders, so the GX cannot read the 0 to 5v which is what the Scheiber senders output. I’m assuming the GX tank will accept the voltage and convert it to resistance? I’m not sure what you’re thinking with the relays but I don’t think you need them.

The way, I understand the Scheiber sender to work is there are three probes in the water tanks connected to the controller. When you send power to when you send power to the controller, it energizes the probes and gets a reading back for which one is conductive. That tells the sender what level probe is covered by water and which is not. There’s a calibration routine that must make an interpretation for values between zero and 100 based on the probes. I know that when I set up my system, I was able to enter calibration points in CZone based on the voltages from the probes.

As you mention, when using the factory Scheiber panel, when you push the button to access the tank level it sends power to the controller to read the probe voltage, but it only sends power to it when you push the button. It is not sending power to the sender unit all the time. In my CZone set up or on the Cerbo GX it does power the controller all the time. I’ve had mine like this for three years and I’ve never had an issue, although theoretically I’m drawing slightly more power when idle.

I think in your case, all you need to do is power the Scheiber controller. I think if the controller stays powered, it will not confuse or disturb the readings from the probes, it’s just that those readings are available all the time which is GX going want. I’m not 100% sure what will happen with your Scheiber panel, but I don’t think he will hurt anything by just doing a test by powering the controller directly and then pressing the buttons on the Scheiber panel to see what it does.

** Again, proceed with caution and this is just my opinion and my suggestions based on what I’ve learned working on my boat. Yours may be different, your Scheiber system may be different and I also may be wrong! 😂

I hope this is helpful, DM me if you want more specific information.

David

edit: re-read your question and added details.

[toi]

Simpler solution:  add kus (resistive type) sender (ignore old one); connect new sender to cerbo (or tank gx if you wish or have many tanks).  It will require cutting a small hole in the top of the water tank with a hole saw to fit the new sender.  The plastic tank in our 2008 boat has several flat places on the top of the tank for mounting sensors, though the hole pattern is not the 5 hole sae standard pattern.  The cerbo provides the very small amount of current needed for the sender.

[Trevor]

Hello tjurd,

I cant add much after that really great and detailed information from David. Dont be concerned however of the influence of the CerboGx Tank monitor on the readings as the input resisitance of the tank monitor is quite high and should not impact on the reading of the existing monitor. It will simply "sniff" the voltage of the main sender unit without drawing very much current so the influence will be minimal.

Lets know how it goes.

Trevor