Storing the NOCO GB40 Genius Boost in the car is not necessarily a problem, but there are a few things to bear in mind:

- Temperature: The device can be used at an operating temperature of -22°F to 122°F (-30°C to +50°C) and a storage temperature of -4°F to 122°F (-20°C to +50°C).
- Charging and discharging: It is important not to charge and discharge the device at the same time as recommended by FCC regulations.
- Storage: Ensure that the device is stored in a dry and protected area to prevent damage.

Overall, the GB40 Genius Boost is robust enough to be stored in a car as long as the above conditions are observed.