Yes, it can recharge your camera battery. If your camera did not come with a car adapter, you will need to purchase one, which usually comes with a replacement battery charger. A quick search on the net found one at Amazon for less than $5.00. Make sure the charger is specific to the camera model. The EOS is very specific on it's input power, so using the USB cable could have disastrous results. Essentially, you need the Canon charger, but with a car adapter. The Canon charger prevents the battery from being overcharged. The time necessary to charge the battery on a long, bright, sunny day is two hours minimum, since the battery charges to full in 110 minutes with the 110v AC power adapter. In real world vs. ideal, I would say it's closer to three hours with the 14W version and 4 - 5 hours with the 9W.

Yes it would. You would carry the battery charger and plug that in to recharge the battery. The USB cable would not work for recharging.