Slashdot Mirror
Tesla Model S Has Bizarre 'Vampire-Like' Thirst For Electricity At Night
cartechboy writes "The Tesla Model S, for all its technical and design wizardry, has a dirty little secret: Its a vampire. The car has an odd and substantial appetite for kilowatt-hours even when turned off and parked. This phenomenon has been dubbed the 'vampire' draw, and Tesla promised long ago to fix this issue with a software update. Well, a few software updates have come and gone since then, and the Model S is still a vampire sucking down energy when it's shut down. While this is a concern for many Model S owners and would be owners, the larger question becomes: After nine months, and multiple software updates,why can't Tesla fix this known issue? Tesla has recognized the issue and said a fix would come, yet the latest fix is only a tiny improvement — and the problem remains unsolved. Is Tesla stumped? Can the issue be fixed?"
No, because it's not using '180W'. It's using the equivalent of 180W draining for 24 hours. Compare with 180W draing for 5 minutes, the time component is important.
The on-board systems continue to suck juice from the vehicle's batteries overnight because Tesla has temporarily disabled (or diminished) their sleep mode due to some issue waking them back up (incidentally, that makes this issue hardly mysterious or "bizarre").
Sometimes the simplest answers indicate someone didn't RTFA.
Tesla Model S uses a proximity sensor to detect the key fob in your pocket and extend the door handle with a motor:
http://www.consumerreports.org/cro/news/2013/05/video-sci-fi-wizardry-of-the-tesla-model-s-doors/index.htm
To quote from an article:
"From the instant you walk up to the Tesla S and the door handles motor out of the door, you know this isn't going to be like any other car you've ever driven. You open the door and the air conditioner has fired up, and your music is already playing. You put your foot on the brake, shift into gear, and you are off and running. There is no âoestartâ button. When you arrive, you just get out of the car; it turns itself off and locks up as you leave."
Tesla originally had a sleep mode for the inboard computer that was supposed to consume around 1%/day. But they found that the sleep mode often resulted in the car not detecting the key fob. So they disabled it until they could patch it. Not surprisingly, it sucks a lot of power while its sitting in non-sleep mode waiting for someone to walk by with the right key fob. If they had stuck with a manual door handle and a push start button for the engine, then the idle power issue would never have come up. In any case, Tesla is working on it and will resolved it eventually.
Again, I love it when non-engineers talk out of their ass. Even top-o-the-line Fluke's don't go over 10A. They all need current clamps which are just one side of a transformer coil to step that current down into a usable range. If you want to directly measure high currents without said clamp, then you're still toting around a big ass ammeter which are still fairly expensive since they contain quite a bit of copper to carry that load. You won't be using a handheld meter for sure.