Tesla Model S gets 90 kWh option and cheaper entry-level

Tesla is offering a larger 90 kWh battery pack for the Model S, extending range, while also making its entry-level electric car more affordable. The new battery, a $3k upgrade, will be offered as an option on all 85 kWh Model S cars, improving range by 5-percent. However, those wanting to get into their first Tesla might be more interested in the cheaper Model S 70, which CEO Elon Musk says is comparable with a $50k gasoline car.

That's based on the newly-discounted car's $70,000 sticker price and the typical $10k state and federal subsidies offered. Throw in the average gasoline savings over the typical five years of ownership, Musk calculated, and you get to that $50k figure.

The single motor car is $5k less than the dual motor version, which Tesla says is "consistent with the price differential for the single and dual motor 85 kWh car."

As for the larger battery, 5-percent might not sound like much but it works out to around 15 miles more. On the Model S 85D, the current version of the car with the longest-range, that works out to around 300 miles of highway range at 65 mph.

However, while it'll be available as an upgrade for existing cars, Musk says he doesn't recommend it "unless your usage is on the edge of current range."

"On average, we expect to increase pack capacity by roughly 5% per year," the Tesla CEO said. "Better to wait until you have more time on your existing pack and there is a larger accumulated pack energy difference."