Hi there!
I need to feed an Arduino Uno with a 12v/10Amp battery. Im thinking about using a LM2596 Step down Voltage Regulator, but I don't know how to regulate current. What should I use?
Hope u can help me!
The Arduino has an on-board regulator and it can run from 12V. (You do have to be a little careful if you're powering a bunch of other stuff through the regulator.)
The 10A rating isn't an issue. The Arduino will only take the current it needs.
Your headline says 42V. That's just enough different from 12V to be a problem. Which one do you want: 12 or 42?
You want to buy a LM2596 chip or you're buying a module that has one of those chips on board? If you're buying just the chip, you need some esoteric PCB design skills to make use of it.
There's no need to regulate current. Once you have the voltage at a level that the Arduino can deal with, it will only take the current that it needs.
Assume a 12v, 10amp power supply.
When powering a circuit with a high amperage power source, always fuse the feed.
Let’s say the Arduino takes 40ma from the 12v supply.
You would be wise to fuse the 12v line to the Arduino with a ~100ma fuse, but a 1 amp fuse would work if that’s what is available.
Place the fuse at the power source, not the Arduino.
above 12v the internal regulator can overheat, can use a buck converter ready module to reduce the voltage more efficiently
What about connecting the arduino to a car battery connected via a strp down module, having in mind that the battery is charged by an alternator at about 13.8- 14.2 volts. Do I need to take notice of the amperage the step down module has for the output/input? The step dowon also has a condensator, so I don’t need to wory about voltage spikes? What about electrical noise? Does it affect the analog readings? And if i use only digital reading, deos it present a problem?
Please keep in mind i have limited knowledge about electric .
Even if the voltage is just 12v (definitely if its more near 14v), i d use a step down switching converter to bring the volatge down to a more arduino friendly level of 9v. This way the on board regularor wouldnt overheat and u can also take care of oo er voltage flactuations due to charger etc..
As Larry pointed out, a fuse is a must!
Or use a cheap phone charger to give 5V directly? That will be built to a standard which prevents almost all the nastiness from the car electrical system reaching your Arduino.
MorganS:
Or use a cheap phone charger to give 5V directly? That will be built to a standard which prevents almost all the nastiness from the car electrical system reaching your Arduino.
Well, it might be. 
MorganS:
Or use a cheap phone charger to give 5V directly? That will be built to a standard which prevents almost all the nastiness from the car electrical system reaching your Arduino.
you are thinking about a lighter phone charger? keep in mind that i only have the engine and the basic electric ignition/charging cables. it will be some sort of buggy/ monopost project, so no 12v lighter socket. if i will connect it directly from the battery with a fuse, wil it work?
Yes. You can pull off the case and use the bare board if you want.
Still thinking that a step down is better, i can change tehe voltage and use the 9v port. Can somebody explain what amps do i need in a step down. the 3Amps or the 6Amps?
What else is powered from the Arduino 3.3V and 5V pins?
Hi,
Who's thread is this?
javbus or syka2210 ????????
Tom... :o
So the project modified. I need to power 2 arduinos, a uno and a micro that communicate between them. they power about 7-8 switches, 3 relays, 2 hall sensors, 2 2digit 7 segment led, 1 7 segment led, one 2 row lcd, a step motor driver, a couple of led (5-6).
@TomGeorge, it is javbus's thread, it appears i have streched with my problem on this thread.
syka2210:
...@TomGeorge, it is javbus's thread, it appears i have streched with my problem on this thread.
Hiya syka, here's a problem with hijacking threads: I was gonna send a PM asking (and explaining how to) edit the thread title to '12v', but you can't do that can you? A lot of folks who could help you, bypass this thread instead, because of the stupid title.