Factory option codes · Battery pack
BT70: the 70 kWh pack
The 70 kWh pack of the Model S 70 and 70D built from April 2015 to about April 2016. Later 70s had a 75 kWh pack limited in software, recorded as BTX5.
What it means for a buyer
This code is the 70 kWh pack itself, so there is nothing to unlock. A later 70 on a BTX5 pack is the one to ask about the 75 kWh unlock. The pack code is the pack on Tesla's record for this car, usually the one it was built with: Tesla can update it after a replacement, and one done outside Tesla may not show. It does not change with software, and it is not always the badge on the trunk.
How Tesla records battery pack
Older Model S and Model X pack codes carry the nominal capacity in their digits: BT40, BT60, BT70 and BT85. The 75, 90 and 100 kWh packs are recorded as BTX5 or BTX7, BTX4 and BTX6, and the report reads both forms. Two things the code does not tell you. First, the badge on the trunk is not always the pack: Tesla sold some cars as a smaller size than the pack inside, limited in software, and its record shows that in Tesla's trim code (a 60 on a 75 kWh pack, for example), not in the pack code, so the report says a pack was limited only when that trim code says so. Second, the pack code is the pack on Tesla's record for the car, usually the one it was built with: Tesla can update it after a replacement, and one done outside Tesla may not show. From 2019 the codes change form, BT37 and its successors, and the digits no longer encode capacity. For those the report uses the public option-code lists where they all agree, so BT37 is 75 kWh with Panasonic cells and BT42 is 82 kWh with Panasonic cells, and prints the code alone where they do not.
Check a car
The free decoder reads the Full Self-Driving codes from the factory record for any VIN. The $1.99 report lists every other code. It also says whether the car can have free Supercharging, and how likely it is.