Good equipment 40 €

The voltage converter does the job and converts the 12V DC into AC 220-240V.
The no-load losses are about 0,19A (~ 2-3W).
Frequency: burden Regardless 49,66Hz
Open circuit voltage: 200V ~ (Standby)
Voltage at minimum load: at least 220V
Voltage at about 500W (purely resistive load) 240V
Warning Low battery: 10,6V
Shutdown at 9.6V
Fan starts at a load of about 30W.
Tested devices:
710W electric plow runs smoothly.
500W halogen spotlights + 60W bulb no problem
700W swimming pool pump does not start (hums 2sec., Then the inverter switches off)
450W Hand Mixer is running without problems.
1800W circular saw running about 1sec)
Bread slicer running only partly at (capacity unknown).
95W laptop AC adapter works, but makes strange noises.
Cell phone charger no problem.
Desktop PC + monitor running. (Monitor has no image distortion).
Small radio work, but something rustles.
Digital Schatuhr started smoking ... :( any chance?

Stress test with just 600W for 10min. went smoothly; Device is at room temperature extremely hot (on the side);
The built Leistungsmosfet's (IRF 3205), however, are of good Quality and hold temperatures and currents
easily made. On the input side are 4 MOSFETs, which installed each 2 drive a transformer.

Efficiency at 55W: ~ 70%
Whether the efficiency at higher loads is still rising, has not yet been tested (test follows ...).

Small disadvantage: With a load of 500W, fall off over the lines and the terminals as 0.5V.
Unfortunately, the 6mm² wires and the battery terminals are warm. Battery terminals are even hot!
Remedy: battery by connecting binding posts (the mitgeliferten terminals are sufficient but not optimal).
Possibly use a 10mm².

For this price, really recommended, as well as smaller tool can be operated.
Who also want to use audio equipment or devices without restrictions that require a true sine wave should
but access to an inverter, which generates a true sine wave.