Best way to go is to not use an inverter at all -
P3 charger from DJI store - $85.00 us
I wouldn't even consider using an inverter in my vehicle for operating a charger that re-charges batteries - makes no sense!
FYI: Using an inverter to charge your Phantom batteries..........think about the process here. First off you are taking dc power from the car battery to the inverter which converts that to ac power in the inverter - then the Phantom battery charger is converting that back to dc power to charge the battery (dc - ac - dc). The true intent of the inverter is to power ac equipment from a dc source
There is an argument for using "clean power" (pure sine wave) versus "modified sine wave" (square sine) inverters. It doesn't really matter IMO whether it is a "pure or modified" sine wave inverter for charging the "smart battery" since the batteries accomplish control of charging rates etc. via its own internal power management.
Most common inverters produce a "modified sine wave" (square) and are fine for most applications and are also the most economical. Pure/True sine wave inverters are used for powering up sensitive electrical or electronic items like a laptop computers, stereos, etc.
For charging the battery that extra step doesn't make sense and is more of a drain on the car battery IMO, not to mention more heat created in the process. For me, the
P3 charger from DJI store seems like the best way to go (if you must re-charge while out in your vehicle). Best and safest choice for me however....is to carry a couple of extra batteries and re-charge back at your home or hotel (when travelling).
CAUTION: What is of most importance here is..........if you are going to be re-charging in your car immediately after flying.....the LiPo battery is going to be hot before you charge and it is not a good idea safety wise to re-charge a LiPo battery until it has had a chance to cool down somewhat no matter what you are using to charge it up. Placing the LiPo into a LiPo battery safety bag when charging in the field is a good idea. Keep the battery and charger away from direct sunlight (
like don't place them on your dash) when re-charging in your vehicle.