iPod Classic won't turn on

I use my ipod in my car to listed to music. I’ve left it in there all the time plugged in. A month or so ago, when I turned on the radio and selected media device, ipod, I would get the message, “device unavailable.” After about 10 minutes of driving the device would wake up. I believe the battery was dying and not charged when I started the car.

A few days ago, I started the car and the ipod never woke up. When I got home, I plugged it in to a wall charger. I tried resetting it. It is not waking up?

Does it need a new battery or is there some other way to wake it up? I’d like to know as I have more than music on there and would like to get my files off of it.