The nearly universal method for running a laptop off an auto battery in the US - and the method recommended by the laptop manufacturers I've consulted, is to use your power converter that came with the laptop, plugged into 110v AC. You get the 110v AC from an "Inverter" that plugs into your accessory 12v DC socket (cig lighter) in the vehicle.

A very few years ago, you almost had to go to a computer/electronics supply shop and pay $75 (US) or more for a decent small inverter, but they're now available at places like Walmart for around $30 in sizes appropriate for a laptop, or at truck stops on the highway in sizes large enough to run a refrigerator. You need a BIG battery for the larger ones.

Most laptops here come with a power adapter, which takes care of getting the correct dc voltage and provides all the filtering necessary. Some, but not all of them, include a built in "reserve" that will even keep the computer alive during short power interruptions. The adapter supplied with the computer is supposed to handle all the variations seen on "mains" power that you plug into.

It's now very easy here to find a variety of inexpensive Inverters that will plug into your car's 12V DC socket, and provide an adequate AC output to run your computer "on AC." I would expect that your local market should have similar inverters to provide the appropriate "mains" voltage and frequency for your stuff. With "AC Power" in your car, you can also run any number of other "household devices" - depending on the size of the inverter you get. I have seen some folk in a neighboring camp running a cocktail blender off one. Some of the larger campers have them built in for the TV, stereo console, and satellite dish converter, although these tend to be very large, and expensive, units.

John