As explained in the DC-DC 6~35V 1.0~35V Boost Buck Converter topic, the LTC187 DC Boost Converter 3.5-30V 100W Power Source Voltage Regulator did the trick nicely. I just used it successfully on a camping holiday to run 12V devices from a 6 cell 7.2V battery pack. No min 6V cutoff which would have protected the battery pack so I had to keep an eye on the input voltage but on the other hand this allowed me to run a 12V 48W airbed pump which took the battery pack voltage below 6V which was useful when returning to campsite late and not wanting to keep the car engine running (necessary as car battery is 5 years old and precarious). Converter never got hot except when using the airbed pump so no fire worries. I did disconnect it from the the battery overnight just in case but not sure if this was absolutely necessary. Only downside was the interference it caused with my radio but I guess that’s a problem with any kind of switched mode converter.

I bought a DR-US200189 XL4016E1 from US Amazon.com and it came with no instruction.
The question I have is easy and I’m pretty sure I already know the answer, but I want to be sure, I don’t want to blow anything up. The inputs and outputs have the polarity marked but there no indication which is the input and which is the output. The card has an LED on it near what I assume are the outputs. I assume the LED monitors the output voltage.

My question is which set of connections is the inputs and which set is the outputs?

Thanks, the datasheet pdf file verified the locations of the connections were what I was assuming. Now I know for sure.
Thanks again

I have just received from Amazon Italy DROK DC 7-60v speed controller. I have tested it with a 12v battery as power input and a voltage digital tester and I do not see any variation of the output voltage turning the regulator handle. Have I to make any other attempt or have I to give back the regulator to Amazon? thanks for replying

Question about this product:

https://smile.amazon.com/gp/product/B01MY270ZN/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

DROK DC-DC 5-40V to 3.3V 5V 12V ADJ Adjustable Step Down Voltage Regulator, LM2596 4-way Multiple Output Switching Power Supply Module Board, 5A Buck Volt Converter Transformer Stabilizer
<div class=”a-row a-size-mini”><span class=”a-color-secondary label”>ORDER # </span><span class=”a-color-secondary value”>113-6661619-4194633</span></div>
The three fixed output ports work correctly.  However, the adjustable port voltage does not adjust with turns of the trimpot.  The output is fixed at one volt below the input voltage (input 14V).

I haven’t removed the trimpot to check it out.

Thanks.