Got this delivered today. Pretty big boy there. Can’t wait to use it. But I will have to wait a little bit longer.
They work really well. You can still use pid controlled settings unlike with a ssr.
@Jonathon_Thrumble ,where did you get the idea that you can’t use PID control with a SSR?
I’ve been doing it for years now, so I’m quite surprised. 
I just put a mosfet in my new printer a few days ago. I don’t really notice anything different but I’m hoping that it helps. Lol. I assume it does.
this is just a better mosfet, not an SSR for my looks or? high power ;Mosfet…
and: @Rien_Stouten SSR+PWM they get hot if the frequency is to high
@Este_ban_S Mine never gets above 30 degrees celcius, which is about 10 degrees above room temperature.
So I call it bull.
@Este_ban_S yes this is a mosfet with a pretty huge heatsink.
@Este_ban_S what kind of frequency are you talking about? You don’t even need 10Hz for a heated bed. For 6mm / 1/4” thick aluminum I even used 1Hz for PID. Was it a DC or AC SSR? What controller firmware are you using? A DC SSR is a MOSFET with isolation and protection circuits. AC SSRs are usually thyristors, SCRs or triacs. AC SSRs tend to be fraudulently relabeled if you’re buying on eBay or Aliexpress or some other site that allows random small sellers. So the 25A model might really be a 10A model with a different sticker and that could be what makes them hot.
And that would be enough. 10 amps @ 230 volts roughly translates to 2300 watts heating power.
@Rien_Stouten that seems like an awful lot of heating power. Lol. I wish the U.S. had a higher voltage system. 110v just requires more amperage which just makes more heat. Idk why we have to be different on so many different things. I work as a mechanical engineer and we are constantly having to do things in standard and metric which is a pain in the butt… All the engineers wish we could just switch to metric but we have a lot of customers that don’t want metric because it’s not our standard… It’s irritating to say the least…
My Crydom data sheet shows 1.3% power lost within the SSR, so that’s 20W for a 1500W 120V heater. It’s more than I’d like it to be but the heat sink handles it fine. I expect the data sheet is showing worst case, my actual losses are probably a lot less than that.
@Kevin_Danger_Powers I feel your pain. But you are not alone in this. We, at the other end of this planet still use imperial measures for things like pipe fittings. The tubing we use is metric.
@Rien_Stouten really? I just assumed that the rest of the world only used metric.
@Jeff_DeMaagd you ar right, I aktually use bang bang and a (yes mechanical) Relay a had laying around. but real PWM with a few khz would turn a SSR (as a fet to) hot. so usw slow_PWM feature of Marlin aka soft PWM? Or is PWM default off on the heated bed?
I don’t know how people have been getting kHz switching. Marlin’s bed PWM has always been ~8Hz for me, but then my “current” Marlin is 1.0.3.
Smoothie’s default PWM has been about 8Hz for me too but I go to 1 Hertz so I don’t notice the lights flicker.
7.689Hz Default on Marlin. You are right I was Wrong, my fault.