MPG expectations for a cold prius.

As I recently found out, there are 5 stages to the hybrid operation of a Prius. It seems quite complicated but when the engine is cold, it stays on until it's warm and then hybrid system will run more efficiently. What you are experiencing is just the cold engine effect, it's probably normal until it warms up.

Here's more info on the 5 stages the hybrid goes through.

The Five Stages of Prius Hybrid Operation | PriusChat

 

The Prius always exhibits low MPG during warm up phase. Usage of climate controls and ambient temperature along with other factors does cause the MPG to fluctuate dramatically.

If the Prius is fully warmed up and in Stage 4 (read about the different stages by clicking link in my signature below) you could expect anywhere from 35 MPG and higher. A experienced Prius driver who hypermiles can achieve 60 MPG and more. Winter MPG vs. Summer MPG will be different also. Winter tends to be lower for most Prius drivers.

I would suggest you learn about the five stages of the Prius operation and take the car for a test drive again. This time make certain the car is in Stage 4 and drive the car on the highway at 55 MPH for at least ten minutes using the cruise control. If you see an average of 45 to 50 MPG on the 5 minute display then the Prius should be delivering its average MPG.

A short drive like you took can be misleading to those who are not familiar with the Prius (new buyer...)

Best of luck to you and I hope this gives you the answer you were looking for. Also "Welcome to Prius Chat!"

 

What MPG do you mean, instant, the 5 minute segments, or the average at the bottom of the 5 minute screen?

 

did you reset the average mpg gauge before driving, or were you looking at the instantaneous bar or digital readout?

 

Sounds a little low but possibly car was really cold and maybe 12v battery was low, possibly EV batt charge was low. Over the "warm" past weekend my wife had 55 MPG on our gauge...man I haven't seen that all winter...was about ready to trade it in.

 

Ok, that low figure makes a bit more sense then.

If you get a chance for another test drive try looking at the 5 minutes averages (it's a bar graph that you get if you hit the little on screen "consumption" at the bottom of the energy monitor screen.)

After 20 minutes or so the last 5 minute average should be showing marked improvement, like somewhere around 50 MPG if your speed is under 65 MPH.

 

Hit the "consumption" button at the bottom of the energy monitor screen.


And you get the 5 minute average screen that looks like this.

BTW. You can ignore the numbers on this one, this was just me showing off. Yours will show MPG instead of L/100 km.

 

One thing that I found useful on the Gen 2 is the coolant thermos. Overnight or during the course of the day, it can reduce the warm-up needs significantly. So you might get better fuel economy when the engine doesn't have to warm up as much as from cold coolant and cold engine.