Originally Posted by Flybob
The cheap switching regulator wall warts do not seem to like inverter output even pure sine wave. If you are using solar, you are probably better off using a 12V to USB converter. I have several WW that have non polarized plugs that work great plugged in in one direction but overheats when plugged in the other direction.
You might be onto something. We've used this set up for a bunch of trips, never before with an iPad. Maybe with just a phone, the load vs plug polarization was ok. But this time, the added load of the iPad and possibly plugged in differently could have caused the problem.
It's weird as we've had other wall-warts, none have gotten warm. Im gonna keep an eye on the polarization from now on.
BTW, I just received an 4 USB port, 8 amp total (2 amp each port) lighter style charger. That should do it!