Cheap waterproof power supply fails basic safety and load testing

We have all seen them on AliExpress: dirt-cheap, sealed black boxes claiming to deliver reliable 12-volt power right in the elements. This generic 12V 2A Waterproof Power Supply promises outdoor utility on a budget. But in the workshop, claims on a sticker mean nothing. Real-world testing quickly exposes where the manufacturing shortcuts were made.

Under the Load and Running Hot

Hooked up to a programmable load, the unit immediately shows its true colors. While it technically hits 12V under zero load, the voltage drops instantly to 11.9V at just 200 milliamps. By the time you draw 1.8 amps, the voltage sags to a weak 11.3V. Pushing it to the rated 2 amps triggers the over-current protection, causing the power supply to cut out entirely.

Continuous testing at 1.6 amps reveals a deeper thermal flaw. The internal DK1203 control chip overheats rapidly, cycling the unit on and off. A thermal camera shows the internal Schottky diode screaming past 100°C.

Inside the Shell

Cracking the plastic enclosure reveals a circuit copied straight from the DK1203 datasheet. However, the factory cut critical corners. The datasheet specifies a maximum 12-watt output for this design, making the "24-watt" exterior rating a blatant lie.

Furthermore, the physical build quality is deeply concerning. The transformer features substandard winding isolation, with the primary and secondary windings physically touching at the edges. Under a fault condition, this flaw could reference the low-voltage 12V output directly to dangerous mains voltage.

The Verdict

Apply the classic budget import rule here: always halve the advertised rating. This is a 12V 1A power supply, not a 2A unit. Given the lack of physical safety isolation inside the transformer, keep this device far away from anything humans can touch. Use it only for low-current, isolated novelty projects.