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?
Hello Finn,
I'm in the same situation, with relay 2 burned!
Did you find a solution ?
Did you use a protection diode as suggested by @JustMurph, for the resons he also mentioned. On some loads there is arcing when contacts open and close, there needs to be a way to snub that.
I have not personally opened one. I dont know if where you purchaed from offers repairs?
Hallo everyone!
If you have experience with unsoldering components from electronic circuits, the relay can be replaced.
At Reichelt Elektronik, the Hongfa HF41F 005-ZS installed in my Cerbo GX (information on the relay: 6A, 250V AC; 6A 30V DC coil resistance 147 Ohm) is sold out. Zettler AZ6991-1CE-5DE and FTR LYCA 005V are suitable replacements. Both have the same coil resistance, the same design and even have better contacts made of AgSnO2.
Best regards
Manfred
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.
