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michelg avatar image
michelg asked

Cerbo GX Relay DC Voltage and Amp rating.

Hi everybody,

I need to be able to switch Off / On a small PC running on an ORION 24 / 12VDC 5A. The PC itself uses around 15W.

Is it possible ? And is it better to connect the ORION 24VDC side to the relay or the 12VDC side ? Thanks for your help.

BTW, it will be great to get the precise specs for the relays, as nothing is available in the manual.

cerbo gx
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4 Answers
ur12vman avatar image
ur12vman answered ·

Those onboard relays are generally 1 amp, enough to switch a typical ice cube (automotive) relay. I wouldn't run the orion power through it.

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michelg avatar image
michelg answered ·

Thanks for the reply, but I do need the correct specifications, just to avoid adding cables and hardware in my installation.

I have been reviewing the "forum", and Victron seems not to have provided the details. BTW, do you already installed such "cube" relays and do you have a recommendable model ? I am in Spain.

Thanks, Michel.

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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi all,


I added the specs to the Cerbo GX datasheet just now.


thank you for pointing out it was missing!


And, just FYI, in these ratings its more than the relay that matters. Also the connector, and distances between tracks on the PCB, etc.

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Fabio De Pascale avatar image Fabio De Pascale commented ·

Hi

I just realised that we have the exact same question for the Color Control GX, and the datasheet linked missed the info there, too. Any chance it can be added?


thanks, fabio

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klown87 avatar image klown87 commented ·

Hi there!





First time i post in here and glad to be part of it!


Thanks a lot to @MichelG for posting the question and to @mvader (Victron Energy) for the answer!

I have 2 questions and few tips (maybe)about it,so, let's be a little bit technic now!

-From the table site that mvader provided( https://www.victronenergy.com/live/venus-os:start#comparison_table), it's clear that the relays on the Cerbo GX can andle up to 6A at 125VAC=750W;
Does this mean 3.4A at 220VAC=750W as well?!
screenshot-20220330-000048.png

I mean,i would like to use it to connect/disconnect a load of 1.5A at 220V tops(1Amp most of the time)when alarm occurs...may i???

-These last quoted 'alarms',are they to be considered/configured as the 'I/O' external inputs,right?

If so, wouldn't be great to have the possibility to control the relay with the 'internal' alarms too (Overload for more than 3sec,Low voltage for more than 3sec,Hi Temperature and so on...)?!


About the table site ( https://www.victronenergy.com/live/venus-os:start#comparison_table),i noticed a few things:

-It states that the Cerbo GX has 2 USB host ports and 1 USB power only(Touch GX...5V!?) but then states that 'No 5V outputs' are there...well,i charge my phone on any of them , without any problems (i would guess,at around 0.5A).

-At point 8. it states that 'relay 2 is only available via manual operation; maybe because i installed the new BETA firmware,but, apparently(i didn't try it!),i can use it as a Temperature operation too:
screenshot-20220330-175039.png


-As i said,i updated my cerbo gx to the beta version and it works PERFECTLY!!!(with my system); the only thing is that, being(i guess)an emulator,it requires that the Bluetooth and the Position on the device are turned on(for no other reasons,i guess,seen that you can be in Alabama or in Burkina Faso).

That's all(for the moment )!!!

I hope that i didn't bother any of you and that i've been clear enough,and to get some answers back!

Ps:if you would like to have a look at my Victron system,check out this video( https://youtu.be/f1u6Ds92AA0) that i made with a couple of friends,which came out,accidentally, kind of a commercial for Victron (i want my part on that!!!)

Have a good day ya'll,

Karl.
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screenshot-20220330-175039.png (100.4 KiB)
wkirby avatar image wkirby ♦♦ klown87 commented ·
If the relay specifications state a maximum of 125V then don't exceed that.

With the relay contact ratings, or any switch contact ratings, it is not really the power that you need to worry about. The specified Voltage relates to opening the contacts. When the contacts open an arc (plasma) is formed as the contacts open. When the contact is fully open then the arc will be extinguished if the Voltage is below the ratings. If you exceed the Voltage rating then the arc may not go out and then very soon there will be a fire.

Very nice to work on a project with Marek. Even though I don't speak very much Polish, I enjoy his projects.

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dandenson avatar image
dandenson answered ·

On a related note, what's the behavior if a device on the relay tries to draw more than 6A? I'm running a small 24V10A heater fan in a battery box, it will run on anything down to like 5V.25A.

Will the relay limit to <=6A or will to trip?

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kevgermany avatar image kevgermany ♦♦ commented ·
Use the internal relay as a switch to control a relay that can handle the load.
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shaneyake avatar image shaneyake commented ·
You will break the relay or PCB leading to the relay. We have had 2 relays died this way from fan start up currents. I don't believe it is fused internally.
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