There are two kinds of powers. In many countries, AC power is normally supplied, for example, in the US and UK and many European countries as well. The batteries normally supply DC current.
Car batteries supply DC power and most devices run on AC current. Therefore, you need a power inverter if you want to charge any device with power supplied by the car. You can use the car power to charge any kind of device, only if you have an inverter in place.
The car inverter with the help of the battery in the car can charge only a few devices that too requiring less power. That is the reason the experts advise to use a powerful source of power like a set of batteries and inverter in conjunction, if you need continuous power for a long time or to charge more devices.
Traveling and camping need more devices than before. In the old days, people used to take a couple of lamps and matches for camping. Today we find it difficult to survive without our laptops, mobiles and many other devices that provide us comfort in the wilderness. You need to choose an inverter based on the kind of outlets it has. Some devices use the normal household outlets while some need a USB port.
You need a set of inverter and batteries, that can charge all the devices that you might use or need at the same time. For example, while on a campsite, you need lights, a source to watch movies on your laptop and run the tablet for your children. You also need to keep the mobile charged and maybe a heater and some appliances to cook. You need to choose the inverter and batteries based on this one point.
Having a source of power is important these days. The car is our second home when we are traveling. You can choose a suitable power inverter from the wide variety available easily these days to suit any price range and ensure that you do not any problem even when you are away from any source of power and get all the comforts that you are used to.