Hello everyone,
I'm still new in this forum and I hope to find someone who knows Arduino better than me and its power source. Thanks in advance for any help.
I'm doing a project with Arduino UNO, the Siemens TC35 and a 7''inch display from Buydisplay.com. I'm currently powered all the system with a 12v lead-acid battery (4.5Ah).
Before connect the system at the battery I did a test of code via laptop USB and it works very well.
Afterwards I connected the battery to Arduino via jack and...
First result: The system doesn't work and the voltage regulator on Arduino gets really hot (initially I connected Siemens and display via 5V pin on Arduino).
Second result: I created a 5V line on a strip-board with a voltage regulator (LM317) and the system still not working.
Third result: I used another 12V battery just to create an USB port to connect Arduino (with also a voltage regulator) and all the rest still in a separate 5V line of the previous battery.
The best solution? The last one although the entire system doesn't work anymore after a while.
And as I said the system if powered by a laptop usb works great!
I'm stuck. I'll be glad if someone could help, thanks!
But the point is that Arduino has to work good with 12V anyway, isn't it?
Are you sure about putting a switching regulator to 5V will it help? Does Arduino work in a 7-12V range? Or you said this about the others boards using a dedicated 5V line (Siemens and display)?
However I must still use the 12V battery because is connected to a solar panel that works with that voltage value
I know what you mean but the point is: WHY all project work properly if I power all the system just with 5V by USB?
(I know already the answer of this question but the point is that I get mad if I'm thinking about this)
So now what shall I do? Should I switch the others boards into a stronger battery (10Ah) and leave alone Arduino with 12V lesser battery?
It's not the battery. It is the regulator. When the regulator gets hot (12V [probably more] - 5V x a couple tenths of an amp) it will shut down and things don't work.
You could power the other boards from a different power source, but you will still have an efficiency problem if they need to run on 5V. In a solar power application you probably want the efficiency you would get from a switching regulator as stated by Mark in reply #1.
So instead of LM317 you're recommending me to use, for example, a LM2596 that is more specific for 5V?
Or do you know a component that you would recommend me?
And after get this regulator may I connect Arduino and the other boards at the same battery?
Finally I got a solution, I asked to friend about using his professional power supply and I powered the system with 7V and the system works very well, also with 8V, obviously the system doesn't work with 12V.
The current consumption is about 0.43-0.44A (0.55A with 12V but it doesn't matter anymore)
So just to give me a try I changed the actual configuration of the voltage regulator (still the LM317) with just a different resistance and now the system works!
But I have still the problem of heating of the regulator. What can I do now? I want to save energy as much as possible and I think a switching regulator could be the better solution, do you know a good regulator for my issue?
Vin: 12-13V Vout:7-8V Imax:400-500mA (like for example is this one enough for my project? -> LM25007)
You are wanting to use the Arduino onboard regulator fed by 7-8 volts? Silly.
ta_dan:
I want to save energy as much as possible and I think a switching regulator could be the better solution, do you know a good regulator for my issue?
Vin: 12-13V Vout:7-8V Imax:400-500mA (like for example is this one enough for my project? -> LM25007)
The LM25007 is cheap, but you will then need inductor, caps, resistors... Unknown efficiency... As already suggested get an all-in-one switching regulator from Recom, Traco, Murata, etc., with 5V output and bypass the Arduino regulator.
I don't know if we're understanding each other but as I said in the previous posts, I was trying to power Arduino with a 12V battery directly via jack along with GSM and Display in 5V Arduino pin. The system didn't work. After I used a voltage regulator (LM317) putting it on a strip-board for these external boards, giving 5V to them and leaving 12V directly from Arduino, didn't work as well.
So why am I silly? If I'll use a R-789.0-0.5 instead of LM317 and connect all together via jack supply I think it'll be a good solution.
The Racom part is a switching regulator also. Does your system need 12V, or does everything run from 5V? If it's all 5V, then the switching regulator will extend the life of your 12V battery by efficiently converting 12V to 5V, vs dissipating the extra voltage as heat in a linear regulator (LM317 and the onboard 5V regulator).
Connect the regulator 5V output to 5V & Gnd on the power header, Not thru the barrel jack.
Alternately, modify a USB cable and connect 5V/GND that way.
I think I got your point, you recommended to use the 5V voltage regulator to feed all the system from USB port, right?
But now I have this question: why I can't use a voltage regulator that give 7-8V and feed all the system via power jack? Is it more dangerous?
You can; 440-450mA means the onboard regulator is going to run very warm, up to hot, and may go into thermal shutdown.
If you're going to have an external regulator anyway, why not just use an efficient one that outputs the voltage you need?
I power my AC powered designs from a 5V wallwart. The switching regulator is the same as a DC powered wallwart.
Ok ok, I got it. From 12V to 5V with a switching regulator and then feed separately all the boards in that voltage line, also Arduino via Vin pin without using its 5V pin to feed the other boards, is it right?
No - the barrel jack and Vin are both before the onboard regulator.
5V in parallel from the regulator to all devices, including:
5V on the Arduino power header, or the USB connector; both are after the onboard regulator.
Do Not connect 5V to the barrel jack or Vin - the onboard regulator will reduce the 5V that the board sees.
I thought the 5V pin was just an output pin and as I can see from the overview of the UNO "...supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it."
Thanks CrossRoads, today I learnt something new on Arduino
I'm very unlucky with Arduino. I bought the switching regulator R-78E5.0-0.5 and the system is still not working.
I feeded the system by USB-Port and along with the other boards are connected to Vout of the regulator. I think the problem could be either the 3.3V pin of Arduino that I'm using for the backlight of the display or the current from the regulator is too low (the current consumption is 0.44A)
I'll be glad for any suggestion, thanks in advance!
