HIGH-PRESSURE ELECTRIC PUMP
If you do not think that manual inflation is a good warm-up for stand-up paddle boarding or if you simply find it too difficult, get yourself an electric pump that plugs into a car cigarette lighter.
Set the pressure you want on the dial, press "on" within 10 minutes your SUP is automatically inflated to 15 psi (if more pressure is required, check that the electric pump can reach it, otherwise you will have to finish inflating with a hand pump).
It is usually necessary to leave the engine of your car running during inflation so as not to drain the battery.
Some electric pumps can also operate on rechargeable batteries but they can cost more than €200€.