Hi all! I'm a newbie here so my apologies if this has been discussed. I just got the 2017 Prius Prime a few weeks ago and live in MN where it got REALLY cold really fast. I'm not sure if that's the culprit here. My "issue": my drive to and from work is a total of 12 miles. Before the cold snap, I was getting 28 miles on the charge and the car's electric mileage decreased as I drove it - this was in both "EV mode" and "EV auto". Since the cold, my car has started it's charge at about 24 miles and literally will not move from that position or goes a little down and even up in mileage!! It's so confusing to me. I don't know if it's switching over to gas during this time but it doesn't seem to show on my gas gauge that it has and still displays "ev mode" or "ev auto" on the dash. Also, I was told not to charge the car unless it's needing one. After I get home, and the car is still at "24 miles", it prompts me to charge immediately. Thanks so much if you have any insight to offer to this very-confused first timer!
Sounds like your EV Auto mode is putting the car in HV mode. When in HV the level of charge says pretty stable. I don’t use EV Auto as i don’t understand what it actually does. I run 99.999% EV mode so just I leave it in EV mode.
welcome! 1) cold reduces battery capacity 2) you can tell if the engine is on by watching the current mpg gauge 3) there are many reasons the engine will come on, especially in the cold. but one that you can control is front defrost. that always starts the engine. another is your heat setting, depending on outside temp. i think 14f is the threshold for the heat pump, but the engine might fire anyway, depending on other factors. leave it in ev mode, not auto.
If it's below 14°F, the engine will run for heat so that's probably why you don't see the charge distance (28 miles) reduce - it's using the engine to power the car, since it's running to heat the cabin... might as well use it for moving the car. It goes up because the engine can charge the battery if it's producing more than it needs to power the car or run the heater (and it does so because it's more efficient than running at a lower rpm) The prompt isn't to ask you to charge immediately. It's just telling you that if you plug in a charging cable, it will charge immediately (as opposed to delay charging. You can delay the charge by setting up a schedule to tell the car to charge overnight instead of the evening for example).
The dealers are usually worse than useless when it comes to informing their customers about the Prius, and especially the Prime. If you go to Welcome to Toyota Owners you can download PDF ver sions of the manual. They are much easier to search that that giant tomb the Toyota puts in the glove box. This is a car where it really pays to peruse the owner's manual. It is a fantastic car, but does have a bit of a learning curve if you want to get maximum enjoyment from it. Here's another great source of info -- Toyota USA - How To Videos | PriusChat
On my 2020 Prime, I've been noticing the same. When the heating is on beyond a certain level, or if you activate any defrost feature, it will go to hybrid mode. From what I can tell, decreasing fan speed or turning off the defrost function will allow it to return to EV, though not without some delay. Tideland Prius is right about the "Charge Immediately" notice -- it's not an invitation to charge, but rather an indication that no charging schedule has been set up.
That is normal behavior with the Prime. As the temperature gets colder the Estimated EV Range goes down. It only starts to go back up fairly steadily as warmer weather arrives in the spring. In the picture above that graphic of the car (to the left of the speedometer) will show when the gas engine is running with red lines between the front wheels or red lines from the gas engine graphic shown in light blue in the upper left corner of the car graphic. The yellow lines show electric from the traction pack being used and the lines also show which components in the hybrid system the electricity is being used by. When you see green lines on that graphic it means the hybrid system is regenerating electricity to the Primes traction pack, typically known as the hybrid battery, That graphic is is just one screen of the Multi Informational Display (MID) , It's controlled with the buttons on the right side of the steering wheel and shows many gauges and settings by scrolling through them using the buttons on the steering wheel. That's a very subjective statement and can be intrupreted in many ways. ie: when does the Prime need to be charged? One answer to that question is the Prime never needs to be charged, it can be driven without ever plugging it in to charge it. (not many Prime owners would ever drive the Prime without plugging it in), but it can be done if that is how one wants to use the Prime. So don't ever be afraid to charge the Prime whenever you find an opportunity to plug it in. As you become more accustomed to driving the Prime in EV mode you will begin to figure out some of the more confusing parts of the Primes systems. I hope you have already figured out how to use the Pre-Conditioning function, found on the Primes Key Fob. The Prime can be Preconditioned in colder and hotter temperatures while plugged in. Preconditioning helps prepare the car to be more efficient, especially while in EV mode. Welcome to PC..
