Shortround6
Major General
The battery in my motorcycle was bigger than that12v 20A lead acid battery
You are not going to get very many tries on starting with such a small battery.
There may have been an external plug. Depending on conditions (temperature? number of aircraft to be launched? time of flight on last flight to charge battery? ) the crew may have cranked, or used a battery cart (if available) or used the internal battery.