Is the MX_LM2596S (image) a good solution for providing power to Arduino Mega (+ possibly attached nano) from a nominally 36 V accumulator , lead acid or lithium ion, max voltage around 40V in practice? This is one off hobby project for myself, learning.
I bought the circuit board from DX.com, SKU154907, DC 3~40V to DC 1.5~35V Voltage Step Down Transformer Module , 3.20 USD from China incl. freight (!).
I tried to find out the specifications for the input side capacitors, in vain. The main circuit, black without visible markings in the image, is LM2596S and there is ample information about that in the net. Texas Instruments gives advice e.g. about the properties of the capacitors in their datasheet of LM2596.
I took a risk and connected an accumulator of 38.8V voltage to the input side of the module, adjusted its potentiometer to give 5.0 V (it did …), and connected the output + and - to the 5V and ground of an Arduino Nano. No smoke, and the Nano blinked happily. Then another test, potentiometer to output 7 V from the module, and plus side to the Vin pin of Nano. No problems, blinking ok. Next the connections were moved to Arduino Mega. Good.
But I am still very worried, if there should be protections against voltage spikes from the lead acid battery during connecting/ disconnecting etc. If the capacitor’s voltage tolerance is not high enough (how much needed?), what happens when it fails: short or no connection?
Is this a viable solution and something to improve in it?
What do you think?