why does it sometimes says that EV mode invalid , I have an EV button original on my Prius and when I have full charge and press the button it says EV mode invalid , why?
And, believe it or not, the HV battery being very full is one of the parameters that prevents EV mode. FYI, do not try and run your Prius as an EV. It is not an EV, it is a hybrid and works best when the petrol and electric motors work together. Let the control software dictate when and how much electric to add to the mix. EV mode is designed just to move the car a short distance (like 100 m) to shuffle it around a driveway, in/out of the garage, stealth approach to home late at night (last 50 - 100 m), etc. If you try and run it like an EV, you will get worse (higher) l/100 km not better (lower). Hope that helps.
I'd say the same. Also, if you're going to move the car in the driveway or something like that and want to use EV to save starting the engine, you need to push the EV button less than seven seconds after powering it up. If you wait till the engine starts, EV will be unavailable till the engine finishes the first stage of its warmup.
