According to the profiles Bill Peters and his electrical specialists calculated, it was possible to power the LEM with just 12 amps. Under normal conditions it needed about 55 amps of current to run.
“The first burn, Griffin explained, would be a long one. Pushing the descent throttle all the way to the full position, Lovell would leave it there for more than six minutes before shutting the engine down.
This maneuver, which for simplicity’s sake Griffin called the superfast burn, would put the crew down in the Atlantic Ocean on Thursday morning, just thirty-six hours from the scheduled PC+2 time later that night.”
Electricity was in short supply. A fully functioning, up-and running LEM required about 55 amps of current to operate.
Lovell toggled the “master arm” switch to On and glanced around to see if everything else was in order. Guidance control was set to “Primary Guidance”; thrust control was on “Auto”; engine gimbals were enabled; the propellant quantity, temperature, and pressure looked good; the ship was maintaining the correct attitude.