diy solar

diy solar

Control a circuit powered by the load output of the Victron SCC with the Cerbo GX relay

tomashubelbauer

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Joined
Nov 12, 2022
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26
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Prague
Hi, I have a Victron SmartSolar 100/15 MPPT SCC connected to a Cerbo GX for remote control via VRM and VictronConnect.

I am currently not using the relays on the Cerbo but I know they can be both connected to a manual mode (and one can be programmed which is not something I need right now).

Right now the load output of the solar charge controller is set up with the streetlight mode turned on so it only comes on during the night. When I don't need this, I switch the load output from Always On to Always Off. So, in essence, it is a two-stage switch, one controlled by me and one controlled by the day/night cycle.

I would like to have two separate loads instead of one and be able to control them manually, remotely and individually. I still want the whole thing to only come on at night, but in addition to that, I want to be able to turn on and off either of the two loads manually and remotely.

Since I am not using the Cerbo relays I figured they would work great for this. I can control them in VRM and if I hooked up each circuit to each relay, I would have achieved what I want with no extra material or effort, I could just use what I have and be able to monitor and control everything from one place.

The problem is that I am not sure if it is electrically safe to connect the load output of the solar charge controller to the controlled side of the relay? I know relays are meant to control one controlled circuit/system separate from the controlling one and AFAIK the two system are expected to not be galvanically connected. This got me wondering if by connecting the load output of the SCC to the controlled side of the Cerbo relays I would be connecting stuff I shouldn't and could damage either component.

Is it safe to connect the load output of the SCC to the relays on the Cerbo? Here's the circuit I have in mind:

1691522199736.png
It is slightly chaotic but it shows that the ground of both sides of the relay is shared and that's where I wonder if that could be a problem.

BTW am I correct in assuming it is not possible to control the Cerbo switches in VictronConnect, only VRM?
 
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