Back to 48VDC Air Conditioner:
In my opinion the key spec to look for when it’s announced is the Energy Efficiency Ratio, or EER. The main reason for having a DC air conditioner will be to get more cooling out of a given battery bank capacity, and if it doesn’t improve significantly over a standard A/C powered by an inverter, then what’s the point. Elimination of an inverter itself doesn’t seem enough.
A big plus will be if it can run more efficiently at lower capacity (running compressor slower) which could extend run time at night even more.