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joeccv avatar image
joeccv asked

Multiplus assistants and Cerbo GX Relays

When installing a system with drop in batteries, I would usually install a thermostat controller to regulate the enclosure temps and then I also program the multiplus with an assistant to run a fan when the multiplus fan is on. Because the enclosure it is mounted in is quite small, this keeps things well ventilated. With this method, two fans are required, one from the t-stat and one from the multi.

I just completed my first system with a cerbo, lynx smart bms and smart lithium batteries. I never want to go back!

My questions is, how can I use only one fan, connected to the cerbo, and trigger it to turn on either via a temperature sensor (mounted in the cabinet) or via the multiplus assistant? Has anyone done this?

MultiPlus Quattro Inverter Chargercerbo gxRelayAssistants
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maa avatar image
maa answered ·

you add a RUUVI in the right place, then you put your fan controlled by the Cerbo relay which will find your trigger setting

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joeccv avatar image
joeccv answered ·

Where do I connect the cerbo relay to the multiplus trigger setting?

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pwfarnell avatar image pwfarnell commented ·
If you are using the Multiplus relay for the fan then you can connect the Cerbo relay in parallel with the Multiplus relay so either one will turn on the fan.
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joeccv avatar image joeccv pwfarnell commented ·
I guess this is possible, but I'd be concerned with backfed circuits and odd behavior. I'd prefer to have it wired and controlled only by the Cerbo relay, with logic.
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pwfarnell avatar image pwfarnell joeccv commented ·
How about connecting the multiplus relay to one of the Cerbo GX digital inputs and activating the relay when the Multiplus fan is running. The Cerbo digital inputs just need a dry switch to function so no power cabling. The Cerbo then knows when the fan is running or the temperature is hot. Code up a node red flow to activate the fan relay on the Cerbo on either condition. I do jot think the native relay code will handle this.
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maa avatar image
maa answered ·

Watch this video and you will understand everything: HERE

But with the RUUVI it is much simpler and more reliable as a temperature sensor

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joeccv avatar image joeccv commented ·
Thanks. This part is clear, but can the same relay also be controlled by the multiplus assistant setting?
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maa avatar image maa joeccv commented ·

I don't think that VEConfig's Programmable Relay Assistant can do this job as well, their role is more focused on managing the interfaces (out & in, AUX, ...) of the Multi according to existing switches in the Multi and no sensors added like a RUUVI

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