Hi

If your SSR has ~ 1V drop at 20A, at 60A the drop will be higher. That puts the dissipation up in the 80 to 100W region pretty fast (at 60A). The rated heatsink you are supposed to use with them is good to *maybe* 20W. I'm running a 100A Fotek off of Amazon. Price was < $20 so who knows what it really is.

Bob