I will be renting a RV in Alaska that does not have an inverter. I need to purchase an inverter that can run inside the unit connecting to the cigarette lighter to power my CPAP machine. I want to be able to use the CPAP machine with the humidifier and heat tube features engaged. Is there an inverter made with a cigarette lighter connection that has sufficient continuous wattage power to run my CPAP machine with these features engaged, and if so, who is the manufacturer and what is the model?