In that case I would use DC/DC converter . Laptops for example have DC input roundabout 15-19 V , so it is not really useful to convert the 12V DC from the solar panel to 230 V AC . The power supply of the laptop anyway convert it again to DC . There are too many losses and the 12V DC to 230 V AC produces not a really good sine wave so it will kill your power supply one day . and anyway , it will not work . This unit you are looking for is an inverter and a charger for battery backup of the solar system and it needs 230 V source to work . This system is a good choice to use it as a ups for computers and emergency power for anything else , but it won t work as an independent power supply