Review on Samlex SSW-600-12A: High-Quality 600-watt 12V Pure Sine Wave Inverter by Jason Page

The big problem with this device is that the fan runs at high speed whenever the load exceeds 45W, even when the device is cold. The fan is noisy, much louder than a normal computer fan. It's annoying in a quiet room. The fan must be variable speed, with the speed being determined by the internal temperature of the device. When switched off, the device consumes 3.3 mA. Switched on with no load draws 520 mA. The high voltage cutoff is 14.8 volts. Low voltage alarm, continuous loud high-pitched squeaking starts at 10.9 volts. The alarm cannot be deactivated, so the device is useless below this voltage. Efficiency was measured at several power levels by calculating (power output)/(power input). Only resistive loads were used, power factor = 1.0, hence the efficiency is (output voltage times output voltage)/(volts times input voltage). The DC voltage was measured directly at the inverter power terminals to eliminate losses in the external wiring. Output parameters were measured with a P4400 wattmeter. At 21W (118VAC x 0.18A)/(14.1V x 2.17A) = 0.69 At 57W (117VAC x 0.49A)/(12.6V x 5.82 A) = 0.78 at 136W (115V x 1.18A) / (11.5V x 13.2A) = 0.89 at 242W (115V x 2.11A) / (12, 6V x 21.8A) = 0.88 at 544W (116W). AC x 4.69A) / (11.8V x 54.6A) = 0.84 @ 580W (115VAC x 5.04A) / (11.7V x 61.0A) = 0 ,81 At 590W, the device shuts down, even with high voltage input spikes. At the lowest voltage used, the efficiency is: at 545 watts (111 VAC x 4.91 amps)/(10.9 volts x 65.5 amps) = 0.76 With weak stations, there will be some background noise when the radio is turned on. Small variable speed power tools work well. Verdict: If they fixed the fan issue, it would be a decent device.