I took out the TXV that can't be adjusted without evacuating the system, and put in a needle valve plus the cap tube.
That let me restrict flow as temperatures climb to keep a constant 4.6 amps.
I tried wood then a metal cover for the condenser coil to restrict airflow so I could simulate a hotter day. The leaky stack of lumber gave better results; the metal cover seemed to cause greatly elevated current for the same temperature. Something about too much of the coil not being cooled at all. The metal cover is shown in the picture.
As liquid line temperature got above about 95F, the BTU perfomance starts to fall off rapidly. I'm able to get 13.6K BTU's at 90F, 13.0K at 94F, 10K BTUs at 102F. Then it falls on it's face, and there's no chance of it not being adjusted properly, since I was doing it manually while watching compressor current, every so slowly.
So evaporative precooling is a must; my former LG window unit doesn't have the advertised 12000 BTUs, EER of 11.3 at 95F ambient at my elevation, at least. (95F would be 110F liquid line temp at 15F approach). I'm not getting anywhere near this performance at 95F equivalent liquid line temps. More like 4000 BTUs.
I can likely live with the needle valve/cap tube combo, but could get the best cooling performance with an electronic expansion valve and custom microcontroller programmed to adjust for max rated amps. They are cheap, but no one but me could maintain it or appreciate it.
