Relay board meltdown....

Hey guys,

I know I am not the only person that has run across this.
I had a bit of a meltdown on my J2 connector on my relay board.
I discovered this as I had a fan that was plugged into this board as well stopped working.
The 12gauge wires that were clamped down on the J2 terminal connector got super hot and melted the plastic insulation. The Green Terminal connector also melted a bit and the whole connector lifted off the PCB and shifted. The solder for that green connector looks burnt now.

I'm a bit worried about this as I know that the wires were securley clamped/screwed down. It seems to me like the solder joints between the green J2 connector and the PCB aren't sufficient for the task to run a 12" heated bed?

Things like this worry me due to the fire hazard.

I haven't had this issue yet, but the number of times it's been posted really concerns me. Automotive relays were suggested in some of the other threads. I am thinking about getting one of these before I encounter I have a run in with this issue.

I think the fault lies with the Green terminal connector. This meltdown had all sorts of side effects.... It burned the wires for my Hexagon cooling fan so that stopped and then my filament mushroomed at the top of the hot end. Then the cooling shroud burnt up. My hobbed bolt got all filled full of filament crap.

The cool thing is that I built this sucker so I know how to pull it apart and fix and repair and all that crap so not the worst thing ever. There are a few points of failure with a MF kit that can have very bad consequences from a fire perspective though.

1st is if your hot end thermistor pops out or becomes loose, the heating element will just keep going to try to heat up the hot end.
Same thing for the heated bed as well.

I have been thinking about some ways to put in a backup emergency shutdown for those two items.

The relay is fine and working 100%. I don't think we need an automotive one for this, but taking off that green connector and soldering straight to the PCB should fix the issue.

I've had a green terminal connector on the relay board melt down, too. I've since replaced it with another green terminal connector, and haven't had a problem since.