We’ve long questioned just how reliable batteries in electric cars will be in the long run. After all, we all know how poor our laptop charge levels are after a year or two. And now it seems that the batteries in the Tesla Roadster are likely to be destroyed beyond repair if left to completely discharge.
It seems that despite safety systems built in to the Tesla Roadster to stop the batteries ever fully discharging in use, they can – and have – discharged completely when left idle. That will happen in around 11 weeks if left fully idle when charged, or as little as a week if the batteries were significantly depleted when the car was parked up.
The drain on the batteries from background sub-systems on the Tesla continue to deplete the batteries even when the car is parked, and if complete discharge is hit then the battery bank effectively becomes a useless ‘Brick’, with the only remedy to replace the battery bank at a cost of around £25,000.
So severe is the demise of the battery bank after full discharge that the motor locks and the Roadster cannot even be towed. So far this total battery failure has happened to at least five Tesla owners, and the cost of replacement is not covered by the Tesla warranty.
It seems that this fault is also evident on the new Tesla S as well as the Tesla Roadster. It appears Tesla are more than aware of this problem and have even been tracking cars – seemingly without consent – to ascertain if the battery is in danger. Which seems like a bit of sensible proactive interference from Tesla in the name of good PR. But why is this problem there at all?
On the Tesla Roadster the cost of £25k is bad enough, but on the Model S it represents more than half the value of the car, effectively rendering it worthless if the battery ‘Bricks’. The only safe way to make sure this doesn’t happen is to always leave your Tesla plugged in overnight.