Remember the Lotus Elise based Tesla Roadster? Or perhaps you still own one, if you don’t or do not, or are about to then Tesla are now offering a battery upgrade, and the banner headlines are not over the top. That’s $29k for a battery upgrade that will increase the Roadsters original range of 245-miles to a more palatable 400 miles. Sounds good doesn’t it, however the more powerful 70-kWh batteries are heavier which goes against the sporting credentials of lightweight sports cars which typically have limited range anyway. So your Tesla Roadster has been upgraded and now has increased range but there is another problem, the upgrade isn’t compatible with Tesla’s Supercharger network. So if you drive from London to Glasgow you’ll be stuck there and have some angry Scottish National Party members to confront. Tesla have opened up the order books for current Roadster owners who can reserve their new battery upgrades for $5,000 dollars. Some owners have already done so. Tesla do not expect to make any money from the upgrade which is completed by hand, Tesla expect the upgrade process to take about two weeks.