Some Tesla Model S and Model X customers in the path of Hurricane Michael will get a little extra boost in the coming days thanks to a remote software update from Tesla headquarters that temporarily increases the battery capacity of its cars.

This is at least the third time Tesla has done this. Tesla did the same thing for customers affected by Hurricane Florence last month and for Hurricane Irma last year. The upgrades provide Tesla customers with up to 40 miles of additional range.

The update is possible because Tesla sold some Model X and Model S cars with more battery capacity in hardware than the customer actually paid for. Tesla sometimes shipped 75kWh batteries to customers who had only paid for 60kWh or 70kWh worth of battery capacity. In other cases, Tesla shipped 60kWh batteries to people who had ordered 40kWh batteries.

Tesla locked the extra capacity in software and offered customers the option to unlock it as an aftermarket upgrade.

Tesla originally shipped these battery-locked cars because it simplified manufacturing to make fewer types of battery packs. Also, doing things this way created an up-selling opportunity—Tesla initially charged $9,000 to upgrade from 60 to 75kWh, though the upgrade price has come down more recently.

Tesla says that some customers in Florida, Alabama, Georgia, South Carolina, and North Carolina will get the free, temporary battery upgrade. In addition, all customers in hurricane-affected areas will receive free use of superchargers.

Tesla is more aggressive than any other car company about pushing out remote software updates that change a vehicle's behavior. In May, Tesla pushed out an update to improve the performance of the brakes on the Model 3 after Consumer Reports faulted the car for its inconsistent braking performance. Other car companies are working on similar capabilities, but the laws in some states require software upgrades to be done at dealerships—a requirement Tesla skirts by not having any dealerships.