xx Car Audio Question xx?

[Vinny x]

I recently bought a car that has a Ipod Cable coming out of the radio.Today I just bought an Ipod Nano 5g from someone.For some reason it will not charge in th Ipod Cable in my car but the will charge on my friends that is hooked up to his pc.Now let me explain the situation in detail.The ipod that I boought is the dark bluish/purple Nano 5th generation.The charger slot is the one that looks like a qaurter slot on a video game.The ipod cable that is in my car does actually connect as well as register on my car radio but it will not charge ..My radio is an aftermarket Pioneer AVH-P6800 DVD system.I would like to know if I am doing anything wrong or whether there is a compatability issue with the cable because the guy who I bought the car from was using an ipod with it but I beleive it was an older one,could this be an issue as well ? Please help me I would really like to know.Also if you want can email me some answers at [email protected] as well TY people in advance.