Hi.

Here is the amazon link am thinking of getting:

https://www.amazon.com/DROK-Numerical-Converter-Regulator-Stabilizer/dp/B01MSJQAKY/ref=sr_1_10?ie=UTF8&qid=1504243552&sr=8-10&keywords=dc+step+down+converter

Project specs:

Input: 40v – 43v (cycles)

Output: 31.5v / 3.2amp

The question is how fast does this discharge? I am using  an LED which needs to shut off very quickly when power is cut.

..or do you suggest a different product?

Thank you