I've just obtained a 150watt inverter to charge my Phantom batteries and remote control when in the field. I have the pro so my understanding is that the charger is 100 watts. All seems to work although I've only hooked up the remote for testing purposes. The lights flash in order so seems to work. My question is how much of a drain on the battery on my old car is the inverter. My cigarette lighter is powered on even with the ignition off so whilst in the field or having a cuppa at a cafe it would be nice to leave it on for an hour to charge the battery. Would this work or would I end up not being able to start he car afterwards?