Hi all,
Is there any documentation anywhere that talks about how to leverage ruuvii sensors and the cerbo gx relay to control my Webasto heater on my boat? The thermostat is famously inaccurate and I am either frozen or burning up! I am not adept at cerbo programming yet but am willing to learn. Thank you!
See the section on setting temperature control of the relay in the manual, link below. I have a temeprature controlled relay and that shows Ruuvi Tags as possible temeprature inputs.
I’m not sure about w-bus. It is the air top evo 3900. Does this literature help?
It’s worth noting I have the MC-04 controller…
You need to:
Pin 6 of X7 connector is the start command pin, but it seems that the current that goes to that pin needs to be limited somehow through a resistor, resistor that already exists on the output from pin 2.
Thanks Alex. My understanding is I need to put an automotive relay between (30a) the cerbo and the Webasto because the cerbo only supports 6a load, and the heater fan causes fly back current on the coil. So, cerbo, 30a NO relay, Webasto.
You don’t need to connect in the way are you describing…
Just take a look at page 29 of your document, when the much simpler Rheostat is used.
The S1 button is for starting the Webasto. It connects Webasto’s pin6 with pin2 through an internal resistor.
The same must be done with the Cerbo’s relay, leaving in place your MC04 controller.
The Cerbo’s relay will act like that push button.
Thanks Alex, this makes sense. One other wrinkle I didn’t consider is that the power button on the controller initiates a shutdown sequence for the Webasto to prevent it from “carbing up” for lack of a more scientific term. I’m not sure if the behavior is the same if you use the relay to kill the power?
The shutdown sequence is programmed inside Webasto. It’s performed automatically.
Button ON - Webasto starts, warm up and work.
Button OFF - Webasto performs the clean-up phase, cools down and stops
It’s all inside Webasto firmware.
Just try it first and play with an external button connected between those two pins.
Then later, if you are satisfied, use as button the Cerbo’s relay contacts.
I have six Bluetooth sensors (Ruuvi and Mopeka) reporting to my Cerbo GX. They’re good but I would be reluctant to use them to activate relays. For my relays that activate warming systems, I use hard wired temperature probes that plug into the Cerbo GX.
Thanks Alex, can you help me understand how I splice the cerbo relay wires into these pins in the X9a connector, and which relay wire goes to which pin? (Cerbo NO to ? and Cerbo Common to ?)
thanks Jim. where do you plug these probes into, and can you recommend which ones to use?
Victron temperature sensors for the Cerbo GX, just connect it to the temperature sensor inputs and set it up, it is all in the manual.
