Estimated versus actual mpg

Since YMMV is even more relevant to PHV ownership, coming up with a generalized difference is highly unlikely. It will take years to confirm too, since it takes so much longer to collect the tank data itself. Here's mine:



Also, I've seen great highway cruising MPG without plugging in.

 

60mpg is totally possible for a long highway trip at reasonable speeds if the AC is not worked too hard. 60mph should equal 60+mpg on a long trip after the car/tires are broken in.

 

Based only on the small number of data points I've collected on my own small sample size of one, LOL, with a 21/79 EV/HV ratio, you can see that my MPG is pretty much in the low 60MPG range. Most of the HV miles are freeway miles, so 55-75 MPH. In summer mode now, so I am pretty sure my EV/HV ratio will invert. However, the actual miles won't add up that fast since I'm not driving 50 miles on HV everyday.

So I don't think the OP's 360 mile trip estimate is off. That's just what you get in HV. Still, HV in the PiP looks to be at least 10mpg greater than the GenII…

 

remember to account for the 3% or higher indicated vs. calculated error between the GenII and GenIII. Overall the GenIII is much more efficient when driven normally.

 

Here are about 100 data points from various Priuschat PiP owners:

PiP MPG Spreadsheet

You can compare the "HSI Cons. MPG" with the "RAW MPG" to get an idea of the variances between reported and calculated MPG.

 

I notice the plugin can store much more juice from long downhill coasts. I also notice the cruise control is flakey - as it will engine brake and regenerate more on downhill coasts, not sure this is a good thing. Having never owned another Prius, I'm not sure if this is a plugin feature. But my old Camry Hybrid did not engine brake regen on cruise control.

 

The cruise on a non-hybrid typically only controls the throttle. If you go down a steep enough hill, you just speed up unless you manually hit the brakes or downshift. Hybrids have the option of recovering the energy on the downhill with regeneration. But the small battery quickly fills, and on the standard Prius anyway, it will engage engine braking (B-mode) to hold your speed. The plug-in has a much bigger battery to store the regenerated energy in, and it is willing to use it. I see this as a benefit.

 

the plugin does not give a calculated mpg strictly on hv with no ev assist like the regular prius, does it?

 

question for the op: if you filled your tank yesterday, why don't you know your actual mpg? and, are you surprised that that 60 mpg calculated is low, or high?

 

can anyone tell me where to find estimated hv mpg's? all i can find is total mpg's which are a combination of hv and ev i think. mine start out at 999 and come down quickly as i drive more hv. i guess if you don't plug in it's straight hv? thanks!

 

that's exactly what i was thinking, thanks!

 

The GenIII is about 5%-6% optimistic compared to the 2% of the GenII.

 

justin, the problem for us is it's using total miles divided by gallons. it's not taking into account kwh used, so when you fill up, there's really nothing to compare it to.

 

I misread his post to mean very little EV miles were included on the tank with that error. Oops.

 

that's right, one tank won't be as accurate as the average of many tanks. unfortunately, many tanks won't tell you how well (or poorly) you did on one tank. this is an issue for all pri, but it's not as bad on gen III without bladder.

 

btw, the hsi does break down ev and hv miles, and also tells you how many kwh and gallons. but for some reason it rounds to whole gallons, so you don't know how much gas you've actually used. i suppose the scangauge would clear up a lot of these questions?