I bought something cheap again.
A Longwei PDS-3010G 30V 10A PSU for CHF 39.- (USD $44.50) delivered.
I haven't found any cheaper 300W PSU.
I didn't expect much but it works so far.
PROS
- 4-digit display. Volt, Ampere and Watt.
- Coarse and fine knobs for A and V separately.
- USB charging socket.
- GND (PE) output.
- It reaches 30V and 10A with reserve (31.7V / 10.24A).
- No overheating problems so far.
NEUTRAL
- The fan is always running, so it's not "smart", but it is very quiet and runs at low speed.
This is probably more pleasant than a fan that keeps turning on and off.
CONS:
- Precise adjustment (4 digits) is difficult even with the "fine" knobs.
- The accuracy is not so good that it would require a 4-digit display.
- In the lower ampere range, the setting cannot be made without a multimeter. You can set the current limit so that you can, for example, power an LED without a resistor, but the display will then be at 0. It can not show as low as 20mA.
- There is no on-off button for the output, but I have not seen any overvoltage when switching on.
- Due to the design (SMPS) there is of course some noise, but I think it is within the normal range (20mV RMS in the example "noise.png").
I'll try to reduce it as shown in the video when the capacitors are here.
A bit concerning: Whether the rear metal parts are grounded (PE) depends on the screw in "screw.jpg".
If this (accidentally) makes electrical contact with the back cover, the parts are grounded, otherwise not.
I scraped off the paint there to ensure contact.
“You get what you pay for”, but yes, it does what I expected and trying to improve cheap stuff is always fun.
Board Rev:20230518