Multiple TP4056 Li-ion in 8s Pack - How much voltage?
I've worked it out. Each module requires 5v at a maximum of 1A. So in order to feed all 8 modules I'd need a power supply that can deliver a minimum of 5v 8A.

However, you can't use the same power supply for all modules when you have cells in series because ultimately it creates a short if you try.

Each module needs it's own isolated power supply.

You can achieve this by using one 5v (min) 8A supply, and by then using one B0505S-1W DC-DC 5v converter for each of the 8 TP4056 boards.
This creates a 5v power supply to each module on their own isolated circuit, therefore creating no shorts.

You could also use diode/rectifier such as 1N4001S connected to each of the negative input terminals of the TP4056 board and then just use one power supply negating the need for 8 B0505S-1W components. The B0505S-1W's also reduce the A down to 0.2A so not ideal, whereas the drop with a rectifier is negligible.