cartechboy writes "Does the Tesla Model S suck down power even when the car is switched off? Recently, a tweet to Elon Musk with an article saying so sparked the Tesla CEO's attention. He tweeted that it wasn't right and that he'd look into the situation. Then a few hours later, he tweeted that the issue had to do with a bad 12-volt battery. Turns out Tesla had already called the owner of the affected car and sent a service tech to his house to replace that battery — and also install a newer build of the car's software. Now it appears the 'Vampire Draw' has been slain. The car went from using 4.5 kWh per day while turned off to a mere 1.1 kWh. So, it seems to be solved, but Tesla may either need to fix some software, or start sending a few new 12-volt batteries out to the folks still experiencing the issue."