rex speed effiency

has anyone checked to see what is the most efficient speed to drive at while running the rex.

I drive my i3 when I am on the REx just as I drive it when I am on battery--on the freeway between 68 and 72 mph. But on occasion I have found it necessary to drive it at 75 mph and even at 80 for ten, fifteen or twenty miles and at all times it delivered the goods. As to efficiency, I have no calculation.

The engine has at least a few pre-set speeds that it will run at. And, depending on how fast you are going, the current SOC, and the load on the batteries, it can adjust. Someone has said that around 56mph is the minimum speed you can go to keep the engine running, otherwise, the load will drop, and the REx will eventually turn off. No gasoline engine gets great mileage when you are running at full speed. I do not know the steps in rpm (and therefore output current capacity), but the faster you go, the lower the efficiency. As opposed to a conventional ICE engine where it is varying all over the place depending on your road speed and load, the REx is optimized to run constantly at certain rpms to minimize noise and vibrations while providing the power it was designed for in the situation you are in.

no science or calcs here but today i did 270 mile in my rex a couple of charges from 40% a 25kw station (22.8 kw showing delivered) in a short time (coffee and a kfc ) up to 96% and it seems 50-60 constant mph is about the best and it cuts out completely just under 20mph. but i only used around 2 gallons of fuel.and when i got home 3 miles on battery left

I've been hammering the rex recently due to a change in circumstances. I reliably get 100 rex miles on a tank, which takes about 9 litres when I fill up.

That's 50.5 mpg imperial, or 42 mpg us.

I try to stick to 68 mph on eco pro, but do creep up to 75 for overtaking.