I've researched this extensively and if you want to get the maximum tax benefit for your car by using your business, what you should do is look into what is called a TRAC Lease or also known as an Open Ended Lease. It is a financial instrument that works very similar to a car loan but structured as a lease so you can write off essentially all your depreciation as a lease payment. You also have the added benefit then of buying the car outright at the end of the lease period for next to nothing.
It's the best way I've figured to buy a Model S and the tax benefits are so much better than a business car loan. As long as you own your business, look up how TRAC leases work and call Earth Motorcars Leasing department. When we buy our Model S, this is most likely how we will pay for it.