SSR or Contactor?

[BottleFed70]

Which one is better?

Looks like you can buy a SSR for cheaper.

I've been looking on EBAY for controllers, and need to decide whether I want a SSR or Contactor.

[CarWiz]

It's a personal choice like Ford-Chevy or what was available at the time for the right price. The SSRs should only be loaded to about 70% of rated handling for heating coils. So if your load is 20A, get at least a 25A rated SSR. Also, for near limit loads you'll need to heat sink the SSR. The benefit of the SSR is that it can be turned on and off directly by most controllers--There's no need to supply additional power for solenoid coils like contactors. Also, the SSR is compact and fits into a small space.

An additional benefit of the SSR is it's switching method. It turns on/off at the zero-boundary of an AC cycle. This helps reduce light flicker and other RF/EMF interference that you can get with contactors. Contactors won't last as long either unless you change some of the parameters in the controller. Most controllers "learn" temperature changes over time so the contactor could be activated as often as every few seconds.

[BottleFed70]

Great info, thanks. Think I'm going to go with the SSR.