Don't use this units in AZ in a non conditioned environment! Even with an ambient of about 25°C (77°F) they running too hot if you have a lot of battery charging power (MPPT or AC-in) coming in. I'm pretty sure they won't last long in high heat environment.
My EG4-6500EX are installed in an conditioned RV garage and it was still not enough to keep them nice cool. I've added an extra small 9,000 BTU ducted mini split to just keep the AIO's cool. Now they always run below 55° (131°F). Also I've added a separation shield between hot air outlet and cold air inlet to prevent the thermal shortcut like
@danthexctman described.
They also loose PV power if the MPPT electronic gets too hot (see manual page 8):
In the picture you can see the separation shields (45°) between each AIO and on both sides (3D printed). This lets the hot air from the bottom separate (at least enough) from the cold air from the top. I "pump" cold air into the upper section which get sucked in from the AIO's. This setup is working very nice now. The 9,000BTU unit does not take very much energy and it's enough to adjust the cooling setpoint just 1°C (2°F) below ambient to blow out enough cold air (I automatically adjust the mini split via smart home rules to regulate the system).
Here is the ducted mini split unit which feeds the AIO's:
From what I've learned, it not required to cool the room (ambient) where the equipment is installed, it's enough and even better to inject cold air just into the units itself. This results usually in a much smaller required mini split which is cheaper and does not consume too much energy.
