Good morning !
I have a project that involves 3 boards and I want to power them up using a single power source (that I will buy, dont have it yet):
It there a way to power them all using one adapter?
And is there a ready to buy solution to take care of the voltage difference for the Arduino?
Whats your experience?
When you have a stable solution for 2) and 3), you can easily feed the Arduino from their 5V too.
Best bet for that amount of current draw is a small ATX power supply. The kind of thing you find in small 1U servers.
Ok, I realiseI can use 5v external supply for the Arduino as well. I was reading about the recommended 6v-12v.
Ok then I have no problem:)
As for the adapter I will use a normal one:
e.g. in UK
I believe this to be sufficient, because all current numbers are for peak levels. So I am 250 mA short if all boards peak at the same time. I will give it a try.
You should be ok, the Pi is only around 750mA, not 1A, so that covers your extra 250mA.
Of course, the power supply is cheaper if you go direct to Lindy, but then you have to have a trade account with them 
Of course, this is cheaper, and gives you an extra 600mA headroom:
You have delivery on top though unless you get past their minimum order level for free delivery.
I don't see the extra 600 mA :
From their specs:
can provide up to 15W
This is max 3A @ 5V . You won't really benefit from a drop to 4V when taking 3.6A ( before it completely switches off ? )
I guess they're pretty similar.
They're Japanese watts. Japanese watts are more powerful than western ones.