s battery and ESC
 

For an 8 cell lipo battery do you always require an HV ESC or would a non-HV esc be okay. I was
thinking of trying an 8s 2700mah 25c battery with a 70amp ESC and a Tacon 110 outrunner on a
13lb Extra 300. In your dreams, what??? Many thanks.

As long as the ESC specs state it can handle 8 cells then it's fine. A HV ESC will usually handle 8 to 12 cells.

I would use a 75 or 80 amp ESC for that set-up and a higher capacity battery pack unless you only want 2-3 minute flights.