I've written two pieces since yesterday on this new controversy which popped up yesterday. It's something for us to think about as EV owners with other kinds of EV's, not all of which have battery management systems. The issue is that on the Roadster, there are systems that stay on even when the car is off, and these systems can drain the battery far enough to kill the battery pack.
Tesla Motors, for their part, released this statement:
All automobiles require some level of owner care. For example, combustion vehicles require regular oil changes or the engine will be destroyed. Electric vehicles should be plugged in and charging when not in use for maximum performance. All batteries are subject to damage if the charge is kept at zero for long periods of time. However, Tesla avoids this problem in virtually all instances with numerous counter-measures. Tesla batteries can remain unplugged for weeks (even months), without reaching zero state of charge. Owners of Roadster 2.0 and all subsequent Tesla products can request that their vehicle alert Tesla if SOC falls to a low level. All Tesla vehicles emit various visual and audible warnings if the battery pack falls below 5 percent SOC. Tesla provides extensive maintenance recommendations as part of the customer experience.
In other words, Tesla is admitting that Roadster battery packs can die because of this. But Tesla is blaming the car owner for not properly maintaining the car. Okay, sure, we all know to plug in our vehicle after every use. This is especially true for vehicles with lead-acid batteries, because lead-acid batteries see actual damage if left sitting in a partially charged state. But this doesn't excuse Tesla from not designing in circuitry to prevent the always-on subsystems from killing the pack, they could have designed it to detect the pack voltage had gone too low and to shut off those systems before voltage reaches the low voltage cutoff.
Here are two blog posts with links to all the news pieces I could find on the subject.
BTW - immediately after writing the second piece this morning, I had this idea enter my mind. That the Eye of Sauron is turning its baleful gaze from the Chevy Volt to Tesla Motors (oh, and Fisker Automotive) ...