This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
I'm having problems wiring up the programable relay on a Cerbo GX device.
I'm using the relay to control an electric water heater that will turn on when there is excess power available in the system.
I wired it up the DC side and the relay in the Cerbo seems to have fried. It's stuck on "NO". Wondering if anyone can suggest where I've gone wrong?
The Cerbo relay is wired to a larger DC/AC relay that the power for the immersion heater runs though.
See diagram bellow:
As per the other thread with my post that you found, it's probably the field breakdown from the big relay that's fried it. Unfortunately you'll need to get the Cerbo repaired, then try again with a protection diode. The setup is just a zener and a normal diode in series across the coil at the relay.
https://www.durakoolrelays.com/information/technology/layman-s-guide-to-coil-suppression/
possibly the current needed to latch the relay? Or the arcing that happens on opening and closing of the contact.
https://www.victronenergy.com/live/venus-os:start#comparison_table
I don't think it's the current required to latch the relay. It was working fine with nothing connected and the relay 2 is still working fine. Relay 2 makes a loud click when manually switching it in the app and using a continuity tester, I can see COM is switching between NO and NC. Relay 1 still makes a small click, but not as loud as before and COM is stuck connected to NO.
I think it must be damaged, possibly by this arcing that happens on opening and closing of the contact. How to wire this up so it doesn't damage the relay in the Cerbo in future?
I suspect a cost effective SSR was used, find yourself a good quality one and it'll likely work fine - however it will cost about 15x what the cost effective one cost.
The Internet is awash with cheap and nasty solid state relays.
Did you find out why your relay fried? I want to do exactly the same set-up with the Cerbo's relay 2 or one of the quattro's relays but I'm confused if a protection diode is required.
I'm already using Cerbo relay 1 wired directly to the quattro's aux 1 (and on to AC out 2) without any protection diode (should I put one?) and its working flawlessly.
I don't want any protection diodes if they are redundant.
F.
However, if you are using a Cerbo or Quattro relay to drive another high current relay or contactor then a protection diode is required, it is a small cost insurance, much better than having to repair your expensive equipment, there have been 2 cases on here in the past few months of people fusing their Cerbo relays driving too high output loads / relays.
I was looking at your drawing again. Why do you have 48vdc going from your battery to your relay when the relay says 32v max?
F.
