The older iPads have 10W power adapter (charger), and the iPhones supposed use only 5W chargers.
But the iPad 4th gen, probably due to the larger power consumption, uses a 12W power adapter / charger.
Is this charger safe to use with the older iPads and iPhones. Will it overcharge or overheat or damage the battery? A more serious worry is that if it overheats, then can the battery explode?