Good voltage transformer with a few limitations

I looked for a voltage converter for my RV to provide even there to diverse devices optimally.
The decision on this device, because it was what I personally have sufficient for my needs 1200W supply and very important, had a mountable remote control with 5m cord lot.
The voltage converter is well finished, has two output sockets, a USB port for power supply, two screw terminals with battery -. Connection cable incl fuse, an on-off switch and a connection for the remote control unit. Furthermore located on top of the device, an information display, which displays the current battery voltage and the direct consumption of the connected devices in watts AC. Using the remote control allows the voltage converter on and off when needed. The information display on the remote control provides the same information as that of the voltage converter itself.
Why only 4 stars:
The fan is controlled temperature and therefore will turn on only when needed. For me it was at a power drain of about 300 watts. Unfortunately, the fan is audible and transfers despite the incorporation in the storage space of the mobile home the fan noise down to the living room. When mounting Wibrationsdämpfer been used.
I also tested the Spannungswandle with various devices. All connected devices such as drilling machine, jig saw, laptop, Reisefön (1200 watts), satellite receivers functioned properly. There were restrictions when connecting a portable radio (noise) and when you try to connect a flat iron. The straighteners showed no function despite only 36 Watt. Here, however, one must say that it is in the voltage converter is not a pure sinewave inverter and there are also devices that can not cope with it even fair to.
Complementing I have still built a mains priority circuit "US-12N" the Board power to protect the voltage converter from external connected power grid.
The fünktioniert so:
If the motorhome powered by an external body with 220V, an automatic isolation to voltage converter. All connected 220V-consumers are thus powered by the external body. If the external power supply separately, is automatically switched to the voltage converter. That's a great thing and funtioniert just great. Can I only know about each. I have the voltage transformer and the mains priority circuit installed so that the refrigerator can be operated with 220V now.
A test showed, however, that in spite of 2 AGM batteries a 90 AH and two 55 WP Solar battery capacity after 24 hours in pure refrigerator mode (138 watts) was coming to an end. (Though weather was for the solar modules not oprimal). Shall therefore operate the refrigerator at 220V only while driving or external power supply. (Removal of the refrigerator about 11.5 A, supply via solar approximately 6 A)
Conclusion:
Top equipment at a fair price / performance ratio. The only drawback is the slightly disturbing noise of the fan, however, turns on only when needed. But noise also feels any different.