I bought the 1st batch of the V2 blades, blue PCB and with a socket for the fuses. There was a little plastic bag inside each box with a spare fuse, you could read "10A" on it. I bought 2 more at a local electronics shop to be safe  .

Later i measured 2 out of 6 V2 Blades how much Ampere they pull at 12V, its 6.5 to 6.8A so you should be ok with an 8A fuse, too!