I bought one of these: http://www.dicksmith.co.nz/product/EA0175/dick-smith-car-charger-iphone

I know chargers for iPhones have a lower wattage (5w) which will charge an iPad, but slower than the 10w iPad-specific chargers.

I'm okay with the slow charging, but the charger seemed to get quite hot in use when I used it for my iPad. I was using it for navigation so the screen was permanently on. I'd even be okay with it not keeping up with the usage, as long as it slows it down.

My question: is it safe for my iPad, my car and me?

Oh and another question: apparently the new iOS will feature an apple navigation system - will it work in NZ?