Esc rebooting
 

Hello
I'm a beginner and i just made my first ever rc plane (i never flew one) and i have a problem with the esc, as i aven't received my connectors i tested it with 9v batteries (first one then two in series) whenever i try to go to high throttle (1/3 with 9v and 2/3 with 18v) the esc shuts off and restarts with the configuration beeps. If i keep a high throttle for extended period of time it does it too. I thought it might be because of the batteries but why would it not work?

I am currently using a cheap amazon 2212 1000kv bldc/30a esc kit
A flysky fsi6
And i connected the 9v batteries with alligators clips to t-plug which came with my lipo charger