12vDC Fuse?

I am using an arduino (nodemcu v3) in a 12-14vDC car application. The nodemcu can take 12vDC directly but get extremely hot. In order to limit heat, Im using a 12-14vdc to 5vdc converter which reduces heat. Should I put an inline fuse on the 12-14vdc leg to the converter?

This is a rough sketch of the wiring
Imgur

It can never hurt.

If you use a 5V converter, DON'T connect that to Vin/RAW but to Vcc/5V. And if it's a Uno, don't plug it into a computer if you power it with 12V.

septillion:
It can never hurt.

If you use a 5V converter, DON'T connect that to Vin/RAW but to Vcc/5V. And if it's a Uno, don't plug it into a computer if you power it with 12V.

thats what I figure it wont hurt. Im guessing a 2 amp fuse should suffice?

Is this guy all wrong on using a buck?
http://henrysbench.capnfatz.com/henrys-bench/arduino-projects-tips-and-more/powering-the-esp-12e-nodemcu-development-board/

Is this guy all wrong on using a buck?

no

Tinkering:
Im guessing a 2 amp fuse should suffice?

No idea. If all that's connected 2A will do but is already overkill. But is you drive servo's, Neopixels or something it might be not enough...

And when I talked about the DC-DC not to RAW I was only speaking for the (normal) 5V Arduino's. An ESP isn't a normal Arduino. And because it needs 3,3V to work, feeding it 5V on it's Vin is fine. But that's only because 5V still has headroom to become the 3,3V the ESP uses.

Tinkering:
I am using an arduino (nodemcu v3) in a 12-14vDC car application. The nodemcu can take 12vDC directly but get extremely hot. In order to limit heat, Im using a 12-14vdc to 5vdc converter which reduces heat. Should I put an inline fuse on the 12-14vdc leg to the converter?

Whoah there! :astonished:

You are talking not about an Arduino, but a NodeMCU, right?

From where did you ever get the notion that you can power the NodeMCU directly from 12 V?

Tinkering:
Is this guy all wrong on using a buck?

Oh! From that fool!

Look, here's the actual circuit according to the makers:

Note that the "5 V" line is directly connected to the CH340, so connecting either 9 V or 12 V to the 5 V line will be subjecting the USB chip, rated at absolute maximum 6.5 V, to that voltage.

No wonder it gets hot - and lucky indeed if you can still communicate with the board! :roll_eyes:

Good thing I disconnected the 12v direct line. What is the deal in the lower left supply voltage limit, 20v?

Tinkering:
What is the deal in the lower left supply voltage limit, 20v?

Sales talk, mistakes.

That regulator (not the NodeMCU) has a max input voltage of 20volt, and a short circuit current of 800mA.
That does not mean they can occur at the same time.
Power dissipation is the main limiting factor, and that has been swept under the carpet.

That text shouldn't be there, because the limiting factor here is the voltage rating of the CH340 chip
(assuming that's not a mistake too).
Leo..

Tinkering:
I am using an arduino (nodemcu v3) in a 12-14vDC car application.

Everything in a car must be fused except the starter motor. Fuses are there to protect the wiring
harness from bursting into flames.

Choose a fuse to match the wiring if the circuit you are getting power from is a higher current rating than
your wires. (Often the case if getting 12V from a cigar lighter socket, which may have 15A fuse itself for
instance)

Or use chunky wires that going to survive with the existing fuse.

Don't expect a fuse to protect the electronics, they should be able to do that themselves, the
fuse is to stop fires when there's a short circuit.