I've recently noticed that sometimes the EV light doesn't come on, even when I'm below the ICE line and I've released the gas pedal and pressed it down slightly again. What causes this?
There are a lot of things that can factor in here. It's not automatic that every time you are below the ICE line, the vehicle will automatically go to EV. It can be dependent on how warmed up or cold your engine is...if it's cold it will run to warm it up to temp. It can be dependent as to how much charge you have at the moment with your battery. And often it can be dependent on what demands you are making of your vehicle. If you are accelerating quickly, to go up an incline, or simply to gain speed, it will keep you out of EV. In anycase, my Prius demonstrates the same behavior. It is simply not automatic that the vehicle chooses EV just because you keep the line below the ICE line. Remember the "S" in HSD....is for synergy. The standard Prius is designed to mix engine and battery. It's not a full electric vehicle, even if designed to run on EV if conditions are correct. Bottom line, as long as it's returning good Hybrid MPG numbers? I wouldn't worry too much about it. If you've just purchased? Be careful, you can become too distracted looking at all the gauges and trying to make certain behaviors manifest. My first week or so, I had to kind of learn to just trust the system and drive it. Then once I became more comfortable as a whole, I've tried to hone my modest and meager hypermiling skills. But I've been very impressed with how great The Prius works...if you just sit in it and drive.
