Could also involve a power surge, maybe in combo with weak 3G signal, maybe not. I would guess that the power supply from a car would be steadier than household power supply, but I don't know much about car power supplies. They sell home surge protectors, so you could use one at home while charging.
You also could see if anything appears on your diagnostics log.
In case you don't know, the iPad diagnostics log is under Settings > About.