Looking just at the nameplate data for one AC alone, it tells you that you should not be adding any additional load onto an upstream 20 amp breaker. The 20 amp is sized to handle the unit's starting current (at nominal 120 volts).
If you look at the electrical code, you will find that for the two ACs and any other loads, you need use the overcurrent device for the largest unit (both 20 amps in this case) and the full load rating of any other loads to calculate the breaker in an upstream panel and wire size. Going by code, minimum wire size feeding two ACs and any other loads is probably going to be just over 30 amps, meaning #8 wire and a 40 amp or possibly 50 amp breaker.
And if the voltage drops causing the AC to draw more current, the situation only gets worse.
