What's the most efficient way to reduce 36V DC to 20V DC for buck converter?

Thread Starter


Joined Nov 11, 2020
I'm building a DC power supply with a 36V DC supply module that needs a 12V fan. I'm using a buck converter, but accidentally bought a 24V max input rated converter instead of a 36V.. What's the most efficient way to step this voltage down so I can use the buck converter I bought?


Joined Mar 30, 2015
Welcome to AAC!
What's the most efficient way to step this voltage down so I can use the buck converter I bought?
Another buck converter.

Instead of using two buck converters, just get one that will convert 36V to 12V. Two converters will be less efficient than one.


Joined Sep 24, 2015
Sorry, wrong one. Try these. $9.99 for 6. 3v to 40v input. 1.5v to 35v out with adjustment pot.

The ONE thing that concerns me is the 35V cap at the output. This is rated to receive up to 40V and output up to 35V. Because this is so close it concerns me. I know you want to operate it at a lower output voltage, and it may be OK. But then again, this design and spec parameters concerns me. What kind of engineer would leave him(or her)self no head room on the output? Makes me suspicious of the whole thing. But hey! You may get lucky and get some good ones. After all, there are over 170 reviews giving it 4 1/2 stars. Just might be OK. I'm going to read some of the negative reviews just to see what you might be dealing with.

[edit] Eh, after reading some of the reviews I don't think I would buy them. But that's ME. The old adages are true: You get what you pay for - and Buyer beware.
[end edit]
Last edited:


Joined Jan 21, 2019
Those work fine for what they are... if you're dropping to 12V not even close to 35V so go for it. I have a bunch of them just in case I need something for a quick project. The 3A output rating is bogus, but should be fine for one computer fan.
Last edited: