Not every laptop can be plugged into the cigarette lighter socket in your car or powered from a solar panel. This is a problem for many users. Unfortunately, the solution is not trivially simple. Cutting the low voltage power cord and soldering the car cigarette lighter plug will not allow you to work with the 12-volt system, because almost every laptop has a built-in the so-called smart battery system. Moreover, applying 12V voltage to a laptop's power outlet will not allow it to work. The original power supply, which I have gives on the output as much as 19V! So there is no way to allow a user to connect the laptop to an automotive battery or photovoltaic panel controller.
In order to solve this problem I decided to build a microcontroller controlled external power module over the power supply from the battery socket to enable operation from an external 12V source. After many struggles I even managed to notify the installed version of Ubuntu about low voltage of the connected battery (i.e. an external battery ;-). Now I can power my portable computer from an external source of 9-15V.
laptop's power socket and module
Smart Battery System is the problem...
reading SBS data
mounting self-made solution
external power socket for 9-15V DC !
external power works well !
solar panel, battery and 8.5V ;-)