The Man says to get a solar panel that will charge what you want will be quite expensive, and will take more than a 160w panel. Being that laptops, tablets, and the like take so much to charge, that's why the car battery would have gone flat. He would recommend getting something like a power pack with a multi charger. I will get what its called tomorrow if you like, but they have an inverter (with power point), usb socket, work light, air compressor, battery jump leads, etc, and they are $149. You can recharge them off the car, and they hold charge for quite a while. He uses it to power his laptop when he goes camping, and I have used the jump leads several times.