I have a sub panel about 75ft from my house attached to my shed that feeds a pool pump, some outlets and a pool heater which is no longer used (50amp). I have built another shed 30 ft from the sub panel which I want to bring power to. I need 1 - 30amp outlet and at least 2 - 15amp breakers to feed maybe 6 or so outlets. I will be installing an 8,000btu ac, a low watt tv, switch for internet and that's probably it. I will be using the 30amp for a couple of crypto miners that use 10amp (2200 watts each) plugged into a pdu. So I am trying to determine how many amps have been brought into and the sub panel. Currently I count a total of 175amps based off the breakers. I no longer use the heater for the pool so that alone is 50 that I can use but not sure how to determine how many other amps are available. How can I tell? 
