Control window unit with SSR

I've bypassed my window unit's internal thermostat and want to mimic the thermostat function (which feeds the compressor) with a SSR, so I can control it thru my BCS.
My previous solution was to kill power to the AC unit when the fins iced up. This took forever unless I ran a bunch of fans. My idea was to keep the AC unit powered up so the fans run then kill power to the compressor.

I tried wiring a SSR in there and the compressor just doesn't like it. I don't know if the SSR output looks different than direct wired. I bypassed the SSR and the compressor works. Put the SSR back in....the compressor tries over and over to start up, but never does.

I'm trying to avoid a contactor, as my BCS can't drive that. I'd need BCS -> SSR -> Contactor.
The alternative is to put a heating element on the thermostat bulb and drive that element from the BCS, however that's going to introduce another layer.

Thoughts?

 

If the SCR source-drain On resistance is reasonable and it has sufficient current carrying capacity, the only thing left is your controller isn't fully turning it on...

Cheers!

 

You must be bypassing the start-up capacitor when you tried wiring the SSR in. They need that to provide enough amps to crank.

 

I replaced the high side of the Ssr with a spst switch and it worked perfect. That tells me it has something to do with the ssr. Sri replaced the ssr with another one I had (both 40a) and get the same thing