How to choose a power supply for Arduino?

Question

Batteries

The microcontroller is planned to work at home in 24x7 mode, so the question arose about choosing a power supply. The block must ensure the operation of 4-6 Arduino boards (1 mega, 1 uno, 2-4 nano), and the operation of a pack of sensors, as well as 2-3 servos. At the same time, the unit must be reliable, not get warm and not be prone to spontaneous combustion or explosions of capacitors. Perhaps there are units with self-control that can turn off when heated or other problems (safety is more important than continuous operation)
I almost don’t understand electrical engineering, and I ask you to help me decide on the following questions:

1. Which block to choose (ideally and where to buy it)?
   
2. Will one be enough or do you need multiple PSUs?
   
3. What length of wiring is allowed from the unit, i.e. can I extend power from the unit to several devices throughout the apartment?
   
4. How to connect several devices to one block correctly?
   

Answer 1

1. Yes, any branded power supply from an electronics store, they are designed for continuous operation at rated current.
2. Depends on many parameters of your development: the location of consumers, the convenience of their connection, common sense.
3. With direct current over long distances, the garbage is like this: either you take toooooooool wires, reducing the resistivity so that the voltage at the other end does not sag, or you send high voltage through conditionally thin wires and set the converter from high to low at the terminal device.
The expediency depends on the specific parameters of your project.
4. Parallel. Do not disdain capacitors near the consumer in case of relative remoteness from the power source.

Answer 2

wagon options. As the most primitive powered by phone charging. Up to 10 mega or up to 20 UNO / Nano can be connected to a standard charger with a current of 1A. It is necessary to apply voltage to the + 5V output, preferably through an inductance of 100-200 μH. sensors, as a rule, consume a small current of the order of several milliamps, with the exception of various radio modules, in transmission mode, they can consume up to 0.5A.
But backup power may be needed, or there are loads that require more than 5V or boards that need less voltage. Here you need to think and deal with each specific case separately.

Answer 3

I like to power arduinos from phone chargers - they just give out 5 volts, which (as a rule) the arduino needs. Considering how much current the arduino needs, the charges do not even think of getting warm. For a couple of years now, I have been continuously (well, except when the electricity is turned off in the house) 3 of these have been working and no problems. True, in order to power 6 boards, one charge may not be enough.