Elon Musk Slays Writer's Vampire Tesla ProblemS

Elon Musk: tech entrepreneur, electric car manufacturer, private space transport pioneer, and now, vampire killer. Not actual vampires — as far as I know, anyway — but the vampire problem that plagued at least one Tesla Model S.

A few Model S owners of late, most notably Green Car Reports writer David Noland, have been increasingly critical of how the car eats through its own electricity at night when it's turned off and parked. Noland wrote that he was losing anywhere between 15 and 23 miles of range at night. This, in spite of a new firmware update released in November that was supposed to fix the problem.

Today, Noland writes that he got a phone call from the scheduling chief at his local Tesla service center saying he had a problem with his 12-volt battery, which runs a host of functions on the car including its stereo and display screen.

I was completely unaware of any problem with my 12-Volt battery. (I wasn't totally sure my car even had a 12-Volt battery.) But apparently Tesla's remote monitoring system had detected some sort of anomaly in the electrical readings from my car.

I agreed to let Tesla replace my battery, of course. Two hours later, a couple of Tesla "Ranger" technicians showed up at my house, and replaced the battery with an upgraded Exide model.

They also downloaded software version 5.8(1.49.25) to replace the earlier version of 5.8 I'd received only the previous week. And then they were gone.

An impressive act of service indeed. And now, Noland says he has since noticed that his vampire losses are drastically less than they used to be, something like 1.1 kilowatt-hours per day, which really isn't bad. But how'd they know?

Noland writes that his original vampire problem story reached the attention of Musk himself, who said on Twitter that Tesla was looking into it. In the end, Noland concludes that his vampire was a defective 12-volt battery. The car's main battery was always charging it, even when it wasn't supposed to, hence the power loss.

But as Noland says, does that mean every Tesla owner who reported a vampire problem has a defective 12-volt battery?

And what about the odd fact that most of the reported problems seem to be in 60-kWh cars? The Tesla spokesman told me that the 60- and 85-kWh batteries are identical, vampire-wise.

While I can now count myself among the lucky Model S owners who has largely been freed of the vampire's dreaded fangs, not every owner is so fortunate yet. And no one seems to be able to figure out why.

Maybe holy water or garlic will do it.