DROK Buck Boost Converter, DC-DC Buck Boost Converter Voltage Step Up Down Regulator CC CV 5-30V to 0.5-30V Adjustable Power Supply Transformer Module

I used this in an inverter that had a variable speed fan. I upgraded the fan and I wanted to run at full speed no matter what the voltage. This module supplies 12 volts to the output after the input is at 5 volts or higher. The output is rock steady at 12 volts. Perfect for a flicking light condition. Drok makes great products.

A good DC-DC converter and is so far working for my purposes. No user manual though.It's a simple product, but I'd really have appreciated a simple instruction manual and/or diagram; it'd just make me (and I'm sure a lot of entry-level users) feel better.EDIT:I was able to obtain a brief un-proofed manual for this, explaining the functions of the two potentiometers ('screws') on the board, and the LED indicators.I've uploaded it for everyone here: http://rnaservices.net/public/manuals/solar/DIY/DATASHEET_200234_boostbuck_manual.pdf

Seems good for the cost - I'm using a couple of these as "float chargers" for sealed lead acid batteries (ham radio portable gear). They do a nice job of taking "whatever" input -- I've tried as low as 5V from a USB phone charger or as high as 22V from an unregulated solar panel and it does an excellent job of charging at 1.5A (current limited) up until it trails off as it peaks at 13.9V (voltage setpoint) very nicely charging my batteries without hurting anything.I had to use trial and error to adjust the voltage and current...the shorter POT with a "+" head is the current, start by tweaking to find the min/max then center it between those positions. Then hook up a volt meter and dial the tall POT (slotted screw head) until you find your desired voltage. Finally put a high current ammeter on the output (shorting it out) and dial the shorter POT until you get the max current you want it to pass. Unhook that and switch back to a volt meter verify the output is still good and you're done.Note that under high load when it hits the max current the output voltage will sag down, that is normal but something you may need to plan for...e.g. if your cooling fan needs 10V to start and you try to charge a battery that drags output down to 9V it may not run your fan.I would suggest planning to build a cooling fan into whatever you use this in, even at 1.5A it gets rather hot for my like without any cooling, though even minimal air flow does wonders (small PC fan works nicely).As others said, the heat sink is barely attached, one of the two I got the heatsink was already broken off so I had to use some thermal epoxy (like CPU heat sink paste, but 2-part epoxy glue that hardens) to re-attach it.All things considered, this seems a very good deal for low-current DIY projects.

Amazing little circuit. Use in my travel trailer for the lights (most are LED). Out put is a constant 12 VDC even if the battery voltage falls to 10 VDC up to 14 VDC. I tested it and ran the input voltage from 6 volts to 30 volts and the output voltage was a constant 12 volts with a 0.5 amp load.

Running this at 2.2A output @ 25V and the bottom of the board is at 175F. Inductor is at 160F. Too hot for my tastes! It would be great for lower output use (below 1.5A).

Stopped working and would not output more than 43mV after about 1 hour of light use (always less than 400mA, usually less than 250mA). Worked great and held a steady voltage across multiple input voltages, until it stopped working. Look elsewhere if you need ANY long term reliability.

Work well and even hot they keep on going.. Nice output low noise and well made. Crazy good price!

Excellent seller, quick shipping and as described! Great deal, Recommend, Thanks