Volt mileage data from 130 mile trip

There have been multiple thread where the issue of Volt MPG in CS mode comes us an questions of real-world tradeoff vs say a prius in medium length trips (say 100-150 miles) of a mostly highway trip. I just did a 130mile trip this week and figured I'd share my data.

We can deal with EPA numbers, with is 35 EV + 40highway so EPA for a 130 mile round trip one would expect 2.375 gallons and 54.7 MPG. A PiP with 50mpg highway and 11 EV miles would use 2.380 gallons. A EPA prius would be getting 48mpg and use 2.708 gallons. Then people here pos their real-world PiP data which is much better so .. yada yada yada..

Real world for a reasonable Volt driver is also better than EPA. My EV mode data is 17% better, over 6000 miles, than EPA. My lifetime CS mileage is above it but not by as much, in part because more than half my ICE mileage was driving the car home when I purchased it.

Below are my screen shots from this weeks trip to airport and then when i got home. I was mostly going with the right lane flow, though I passed a few times. Most driving was at 65mph with a few sections (maybe 10 miles) at 70-75 and maybe 10 miles (all EV) at < 45. Temps were upper 60's going, about 80F on the return. THere was no hypermileing (I had passengers), though of course I maintain a good distance, accelerating and decelerating smoothly. I just went with cruse control as I find it produces better EV range and better MPG.



On the way there I used Mountain-mode to save some EV for the slow sections right around the airport, so I still had 15 miles of EV showing when I stopped. To airport was 35.2 EV miles and 63.2MPG


The screen after the overall round trip.




Round trip it was 48.9miles EV and 46.8 MPG. The fuel used was 12.9kwH + 1.72Gallons for overall 76MPG and 61.8 MPGe. Not too shabby for a 130 mile trip.

I think there is more to the EPA variance with the Volt. Every time you accelerate enough the car may think you want to pass and drop from 2-motor mode to 1 motor. I just went with cruse control, and get better MPG. I think the EPA cycles, which don't have a any real segments of constant speed, make it hard for the car to know when to use two motor mode and when to use 1. It thus makes it hard for the battery buffer to really show its advantage when doing highway driving. I expect the PiP has the similar issues which is why we are seeing many people getting HV numbers well above EPA. Testing PHEVs just has a lot more variations and even more so than for an ICE, YMMV.



So to those that say the Volt's gas milage is poor, I'll just reply that it must be the operators (including those at the EPA), like the people that only get 40mpg from a Prius. My most common runs that need gas is the airport, and in my Volt I'm getting 45+EV and 45+ MPG.

 

Figure I'd update with my most recent trip data -- Nice weather helps though with my passengers I needed to run AC in eco mode.

Today I drove in Mountain Mode so I could save some battery for after the first stop and drive EV in downtown, then did not use mountain mode on the way home. This seemed to help the MPG a bit.



Overall 83MPG on a 130mile trip, and my first 50+50 day :rockon:

 

Unacceptable? Really.. what's your MPG for a 130mile trip in your PiP?
if you could get 15miles in CD and 70MPG_CS, you still would have < 80MPG overall. The best HV efficiency on the PC spreadsheet is 67mpg are you doing better than that? Are you taking lots of 200mile trips? Maybe you should be adding your stuff to the spreadsheet.

What is your MPG over the past month?

 

No mid-station recharge. I measure power from the wall, not what the car reports. (My 2011 does not report anything anyhow).

12.9kWh is what I measured for a full charge in mild weather. When its either hot or cold it can go up to 13.1 or so as the TMS takes added power while charging. (To be honest I did not measure that day, just used data from mild days in the fall. My measurements were between 12.7 and 12.9 when temps were 60-70's)

 

I am aware of MM and what it can do. MM was engaged when I left, so it did not need to "recharge", just work like a hold-mode and saved 18 of EV miles for when I got off the highway in denver. Battery was then consumed on the way home.


This is very common trip for me (either the DIA airport or nearby areas like CU health science campus). I did it many times in the fall, and included using MM to recharge from below its minimum SOC. (At the time I though that MM could get better milage based on some statements from GM engineers about being able to get higher mileage but it would be noiser at higher RPMS). At the time I though I was going great because I was getting 44-45 MPG in CS and 73 overall. If I just did standard, and run it down to CS mode, I was getting 41-42 MPG_CS and 70 overall.

What I have found since then (but still want to verify with torque logging, if I can get it to work on 2 trips) is that by engaging MM when I leave, saving the EV for the city portion, I am getting overall better MPG. The MM games also provided EV in denver, and my guess is that I gained from that but loss by wasting energy recharging. Pretty sure that is the case, but I want torque logs so I can better ensure I'm not driving slower one day than the next. I usually have passengers on these trips so cannot pay detailed attention to my speed, I just go with the flow of the right lane.

 

The 263 just a bit high for me, in this nice weather. My average so far in May is 248 wh/mile. My car starts the day showing 48-50miles of EV estimates range and I probably hit 50 (as 40is real to 10s estimated) 3 out of 5 days a week. Other days I push it harder if I'm running late (i.t. 75mph on the highway). When I have the time I take more side streets and when I do I can hit 50 most days I try. I've had 5 days of actual milage 50 or better CD range since April, but then I've only had 8 days over 45 miles total.

I did worry about MM messing with the stats (it can easily do that if you turn it on when below 40% SOC..). I'm turning it on early so that does not happen but never sure what is going on under the covers. This is is part-of why I really like the 50EV+50MPG_CS day, since there is not much room to "trade" one for the other with that type of performance, its about 30% above EPA in EV range and 25% above it in highway MPG_CS.


I like to think it is because I'm efficient driver. I think many prius drivers could get similar results. Mostly its that the EPA numbers are weak, consistently. Remember, the EPA got nearly 50 miles on a carge then multilied by .7 to provide their official estimate. They presume they overestimate by 30% and multiple to correct.

As I've said in some other posts I think the battery usage is even more sensitive to variations in drivers than the ICE, so there is greater variance around the EPA estimates. If you look at the PC spreadsheet for the PiP, there is also very large variations, even for the same individual.

 

I agree think the Thermo efficacy for EV is better in mild temps though it falls of fast in cold temps. I think the reason for the higher variance is the lack of feedback.. when you push your ICE car hard you hear it. When you push your EV, you don't. When I first started driving the Volt I found my self doing 85-90 without even noticing. (I used CruseControl now so don't get speed creep. ) And the acceleration is addictive, and regen takes some learning.

Yes, so far my computed MPG_CS per trip and what I compute using voltstats.net data (which shows me gallons in the tank) and then what I get with gallons at fillup have been close. First two were underreported by about 1%, last tank over-reported by 2%, but I alway stop on the first click off (volt is sensitive to over-filing) and it was a different station than the first two. Also since the last tank lasted 5+ months maybe there was some evaporative losses.

Yes the thin air can help a bit.

 

if you are 30% worse on EV, and paying for renewable, then enjoy. Otherwise earn some karma-points and find a way to charge green.
If you are 30% worse on ICE, well then maybe should need to get a tesla, so you can bad but still green.

But if you are driving on the wind, its not too bad to have some fun.
There are days when I go into sport+L (especially when giving test drives or when I know I'll have a lot of energy left over, and I'm feeling like fun.