Dual Out Power Supply for 4 and 3.

[splangie]

Is there a two out power supply that can run a 4 and 3 at the same time?

[RossDv8]

The most I can find is a dual outlet USB charger that puts out 2.4A from each USB port for a total of 4.8A. Which happens to be what I am using to run just the Pi 4 for the last couple of days, using both outlets into a single USB female socket via a Y-cable. (USB splitter cable)
The think in the picture with the blue light and 'Laser' written on it, and 2 x black leads into the white lead, is powering the Pi 4. the other stray USB cable on the power board is for something else.

I haven't seen a USB charger with a bigger output amperage than that so far.
There's a good chance one of these 'might' power a Pi 3 or 3B+ from each USB socket, but I think it would not power a Pi 4 from one USB socket.

[splangie]

Thanks for the info.

[RossDv8]

No idea where you are splangie, but if you are an Aussie, I have bought my LASER power adapters from Big-W. They are about $20 or so. The USB splitter cable was cheap off eBay. One lead is meant for data, and one has a REd band on it for power, but either (in this case both) can deliver power.

Which is irrelevant in your scenario of powering two Pis from one adapter, but might be nice to know if you ever kill a Pi 4 power supply.