I want to use my home 4G router in the camper van. It is 240v and 24watts rated. My calculation is that it’s just 0.1amp if that’s correct. We have an Avtext TV that’s runs on the 12v system & so apart from some small led lights will not use anything else when using router to watch TV. If on electrical hookup we won’t have this as a problem but will without. I see there are very simple low cost inverters but am aware the need to be careful using an inverter & the need to take account of the total power being taken from the system and read the is to double the wattage of all power useage when choosing the power of an inverter. Hence the description above of what total power we would be using through the inverter if just watching TV. Wonder if anyone able to give advice. Thanks