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lvaarli avatar image

Cerbo Gx relay outputs

What voltage and power can be applied over relay out out on Cerbo GX? Assummed that the relay output is passive contact. Is the relay out a pulse or can it hold? Is external relay to power consumer required?

cerbo gx
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3 Answers
carl-dewever avatar image
carl-dewever answered ·

I would also like to control the water heater with the relais.
In my use case I could switch on the water heater before I leave home going to the boat so the water is hot when I arrive at the boat.
Therefore, I would love to give relais1 or 2 a custom name and also be able to switch the relais from the remote console on vrm

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billknny avatar image
billknny answered ·

@Lvaarli

You can have a Cerbo Relay 1 actuate based on SOC, just review the manual section on auto starting a generator. I know you are not starting a generator, but it's the same functionality. My understanding is that Relay 2 can not be used in this way.

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lvaarli avatar image
lvaarli answered ·

Any that knows these details?

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Hi @Lvaarli

it's a signal relay, I would not put more than 1A through it.

Max voltage AC: 230V (AC rating tbd, will update later)

Max voltage DC: 30V, for low current (below 1A) you can go to 48VDC also

lvaarli avatar image lvaarli Daniël Boekel (Victron Energy Staff) ♦♦ ·

Thanks for reply. But Venus gx relay output rated 6A?

Hi @Lvaarli

I will get back to you when I have an official answer.

lvaarli avatar image lvaarli Daniël Boekel (Victron Energy Staff) ♦♦ ·

Hi, Any update from victron on this topic?

Is it possible to setup this relay output based upon Battery SOC? Since intended use is to turn a load on off. Thanks for swift reply.

I'm using the relay 1 output on my Cerbo, to turn my boat's electric hot water heater on and off. It's turned on and off based on battery SOC, DC load and time of the day using the generator start/stop function and inverse logic (wired to the NC contact of the relay). This way the solar tops the batteries to 90%, then turns the hot water on and leaves it on till late afternoon when there is no excess solar input. It'll also turn the hot water off when there are any large loads on the system.

I use the built in relay to switch a larger 230VAC relay with a 24V coil and use a protection diode (a normal diode and a zener) arrangement to ensure the field break down when turning off the big relay doesn't fry the little one.

The generator control function is quite configurable, so this should be able to do what you want.

Any questions, please ask.


P.S. Victron, I'd love to see dedicated hotwater control functionality in the Cerbo, with a few more advanced features like multiple temperature set points for different SOCs.

P.P.S. It would also be great to be able to use relay 2 for anything other than manual switching. This seems to be useless?