Hello,
I want to power my Arduino with my car battery but I don't know which method is the best to do that.
So my car battery has normal 12V but when it is full it has something like 12.3V.
I've read that the Arduino can handle 7-12V.
A HC-05 bluetooth module is powered by the arduino itself.
But I also have a unstable 12/24V DC to stable 5V DC converter in my car because of my led strip. So I could take that 5V and power the arduino, but is that smart?
So in total I could power it with my car battery (12V) directly or I could power it with the converter (5V).
I also heard about that you can power the Arduino directly at the 5V pin.
What do you guys think? What is the smartest way?.
DC-DC converter to Arduino 5V pin and HC-05 is by far the best way to power things. It's always worth avoiding the onboard regulator that wastes power cutting 7V-12V down to the 5V the Arduino actually uses.
slipstick:
DC-DC converter to Arduino 5V pin and HC-05 is by far the best way to power things. It's always worth avoiding the onboard regulator that wastes power cutting 7V-12V down to the 5V the Arduino actually uses.
Steve
Ah okay thank you for your answer! But how tolerant is the 5V pin? What is the maximum input voltage? 5.5v?
A car can have voltage spikes. I think that equipment for in a car must be able to withstand a peak of 120V.
It is possible to damage an Arduino board when applying 5V to its 5V pin. The 5V pin is a 5V output to power sensors.
When applying 5V to the 5V pin, then current can flow from the car into the computer when that computer is connected to the Arduino board.
Which Arduino board do you use ?
The Arduino Uno or Nano still works with 5.5V, and it might withstand 6V. You should keep the voltage between 4 and 5.0V.
A good quality DC/DC-converter, designed to be used in a car, with a output of 7.5V or 9V is the best.
If you are willing to take a risk, then you can make the 5V weaker (for example with a 10Ω or 22Ω resistor) and power the Arduino board with it. To avoid a current flowing from the car into the computer, you could use a USB connector with that 5V (instead of directly connecting it to the 5V pin). Then you can connect only one usb connector.
On the Arduino board is a voltage regulator with capacitors. A weak 5V applied to the 5V pin does no harm. The voltage regulator can withstand a reverse current. However, when a strong 5V is connected to the 5V pin at once, then there is a high peak of reverse current that can blow the voltage regulator, possibly causing a shortcut that might burn the Arduino board.
Suppose there is a super powerful 5V available with very thick wires. When a wire with that 5V touches the Arduino 5V pin, that can blow the voltage regulator because of a reverse current peak. Some have indeed damaged their Arduino board.
The Arduino Uno has a polyfuse between the USB 5V and the 5V pin. That will hopefully protect your computer when you connect a computer with a USB connector. But you might have a very cheap clone that does not have that polyfuse.
That said, I also power some of my Arduino boards via its 5V pin So far, no damage here.
So I put my 5.1-5.2V to my 5V pin ? Or do I put a resistor in between?
No resistor. I have never read of or had any experience of a problem. The 5V pin is the best way to power it; with 5V. I don't think 5V2 would be a problem.
The on board regulator is puny and doesn't have a big enough heat sink, it's ok for demonstration and experimenting but really best avoided.
Hello,
Be carefull not to cause fire, care batteries can create high currents with the risk of fire.
Proper fusing is mandatory. You can decide to use short-circuit-proof wires between the battery and your fuse? These cables meld internally instead of causing a fire. So they act as a melting fuse. (Typically they are used for industrial use to connect small measuring devices to a 400V-1000KVA bus bar.)
Be careful with short circuits between the 2 taps of a battery, it can by very vicious during short circuit. If it overheats, it can explode and cause severe chemical burns. The acid was used after the second world war to mutilate people who chose to team up with the enemy.
There are power supply's that are designed to feed USB devices using the grid of a car, have you considered this option?
So far, no damage here.