DC DC Solid State relay problems

Hi Everyone

I never really liked the idea of running 250W for my heated bed through my printrboard, so I just got a SSR. DC DC, 40A.
Connected the controlvoltage on the relay to the Heated bed output on the printrboard- tested it without the heated bed connected, and the LED came on when I turned it on in software.
Connected the load between negative on SSR and powersupply. After 10 secs I could smell something was wrong.

I never got to turn on anything in software.

Question: What am I doing wrong?



Thanks alot!

Jonas

If you connected the bed to the positive on the PSU then you should connect the other wire to the positive on the SSR and the negative of the SSR to the PSU ground.

Seems like you wired it backwards.

---

[www.hydraraptor.blogspot.com]

Thanks Nophead

Should it matter that I place the load between positive on PSU and positive on SSR instead of between the ground?
The datasheet says you can do both.


Jonas

You can do either but the DC SSR must be connected so its positive terminal is more positive than its negative one.

---

[www.hydraraptor.blogspot.com]

Which one is your SSR?

I returned it as faulty, dont remember the name. Back to using the output directly from the printrboard.


Jonas

If the SSR is like these: [www.ebay.com]
it won't work with DC voltage on the output (the high voltage side). Basically it will stay close and will overheat whatever you control. These SSR's only work with AC on the high voltage side