You might drive one of the most desirable sports cars in the world (depending on your definition) but according to News.Com.Au, if you don't leave your Tesla plugged in overnight, you might come back to find it useless in the morning.

The reason is simple - and Tesla is fully aware of it. Tesla's answer to the website's enquiries were that customers were told at hand-over that the car needed its batteries never to go flat completely flat and that it would issue a number of "warnings." A spokesman for Tesla told the website "for us, electric vehicles should be plugged in and charging when not in use, that's for maximum performance and all batteries are subject damage when at low levels for a long period of time, anything longer than a week for a charge to be kept at zero."

That's a fat lot of good if, like this writer, you live in a city centre and use a car only to go out of town perhaps once every couple of weeks. Or for an owner who leaves his car in a car park at an airport while on holiday.

But Tesla has also, reportedly, issued an independent statement in which it says "Tesla batteries can remain unplugged for weeks (even months), without reaching zero state of charge."

The website looked at other alternatives including the soon to be released Holden (Chevrolet) Volt, the Nissan Leaf and Mitsubish i-Miev, all of which are said to have some kind of fail-safe to prevent a battery fully draining if a car is left parked for a long time.