step down converter with LM2596

[obcd]

Hi,

I want to supply an esp32 module (5V) from my 36V ebike battery.
An obvious solution is using a cheap aliexpress switching stepdown converter.
However, most of them seem to use an LM2596 regulator and define 40V as upper input voltage limit.
As we all know, a fully charged lithium battery can go up to 42V.
So, is it safe to use such a step down, or should I place a couple of diodes in front to lower the voltage just a little?

Maybe there are better solutions that would even work with a 48V battery? Any suggestions?

 

[LewTwo]

What do you consider cheap?

https://www.amazon.com/dp/B082QXGR5D
Note the voltages on the capacitors

 

[E-HP]

Hi,

I want to supply an esp32 module (5V) from my 36V ebike battery.
An obvious solution is using a cheap aliexpress switching stepdown converter.
However, most of them seem to use an LM2596 regulator and define 40V as upper input voltage limit.
As we all know, a fully charged lithium battery can go up to 42V.
So, is it safe to use such a step down, or should I place a couple of diodes in front to lower the voltage just a little?

Maybe there are better solutions that would even work with a 48V battery? Any suggestions?

How much current do you need at 5V? Is $6 cheap enough?

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=DC-DC++48V+36V+to+5V+Buck+&_sacat=0&LH_TitleDesc=0&_sop=15&_osacat=0&_odkw=DC-DC++48V+36V+to+5V+Buck+Step+down+Power+Supply+Module

 

[marka-ee]

lm317hv , blunt instrument analogue, good for 60 v I think.

 

[amberwolf]

Some options I've been looking at for my Nano stuff starts at this post
https://endless-sphere.com/forums/viewtopic.php?f=2&t=110497&start=25#p1619867
all the posts with "LVPS regulators" as the title in that thread have various info.


As a note, based on posts here on ES, an unknown number of makers of those 2596 (and other) boards are not using genuine parts, and some will let their smoke out when well within limits they should have tolerated. Mostly it's the HV versions of those that are problematic (likely they're remarking the regular LM2596 as HV, or their suppliers are, and that's probably where most of the failures come from).

 

[obcd]

An esp32 needs around 100mA average when wifi is working. So a linear regulator like the LM317HV would consume 3.5W. It might feed some bike lights as well, so a linear regulator isn't the solution I am after.

I wasn't aware the LM2596HV existed. So maybe buying some cheap aliexpress modules and simply replacing the LM2596 with an hv equivalent is a solution. It just doesn't seem to be commonly available. (Farnell and rs components aren't selling the HV versions.)

Another option (found thanks to the ebay links) is using a step down with the XL7015 regulator. It's only 0.6A but should go high enough in voltage.

Thanks for all the replies. It has been helpfull.