This is a bit cheaper and the model I have. Have left mine running over 24hours in the car. As it's compressor driven the energy use is hardly noticeable tbh
Deal: Alpicool C20 Car Fridge 20 Litre Mini Fridge 12/24v Car Refrigerator Portable Vehicle Camping Fridge Freezer Electric Cooler Box for Truck, RV, Boat, Picnic, Outdoor Travel/ -20℃-20℃
Amazon.co.uk