Hi, been running mine since I get it on about 30% when it's very cold and 70% in the summer. If I have gone on a long trip, I have gone 90% then topped up with diesel near the end of the trip or it will not start. I only use used veg oil and shell V-max. I have my own filter station that takes it down to 1 micron. I did have an Espace that had heaters ( water and eclectic) and run that 100% all year round, and did it for years. You do need to keep on top of it though as it can cause problems if you don't, so would not recommend it. Regular fuel filter changes and the add tank of just Shell V-max.