Real Economy of the Accord PHEV

[rwsimon]

I've had my PHEV for about 5 months now and have a pretty good idea of what kind of fuel economy it provides. I have about 4,000 miles on the car and I average about 800 miles between fill-ups. What does this really mean? Well, the car goes about 15 miles on an electric charge and it gets between 45 and 48 mpg on gas. So what this really tells you is that your fuel economy completely depends on your own individual driving patterns. Most of my driving is local trips and I seldom need to use gas at all. But every few weeks or so I end up taking a road trip to someplace at least 100 miles away and sometimes more. That's when I use most of my gasoline. According to the car's system, my "average" is about 80 mpg, meaning that in total, I drive almost as many miles on electric as I do on gas. If it wasn't for the road trips, it would skewed far more towards electric drive and my average would be far more.

Other owners are likely to have very different results if their driving patterns are different. So unlike a typical car whose mileage is pretty much a standard property of the vehicle (apart from the effects of what kind of driver you are), these PHEVs can provide very different results depending on how you plan to use them. It's something to consider when purchasing such a car.

 

[Cobra]

Yeah, I have to agree. I'm seeing about 70-75 mpg on the Accord per tank of gas. But that ignores electric use. I'd like to see a MPGe estimate on the car. There doesn't seem to be any indication of how efficient electric use is for your electric only miles.

 

[rinthos]

So unlike a typical car whose mileage is pretty much a standard property of the vehicle (apart from the effects of what kind of driver you are), these PHEVs can provide very different results depending on how you plan to use them. It's something to consider when purchasing such a car.

On the contrary...I think non-hybrid/non-plug-in cars also are impacted the same way.
For example, my friend drives a 2012 corolla and to work and back averages 34mpg.
His roommate, for the same drive, averages 21mpg (And he is not a crazy driver, just different style).

How you drive ANY vehicle is the greatest factor.
As a test, drive a regular gasoline car, then drive your PHEV for a month purposefully trying to maximize mpg. Then switch back to the regular gasoline car. Your driving habbits from super-MPG style likely carry over and you've 'magically' improved the fuel efficiency of your regular car.

That said, these PHEVs do have a rather impressive mpg range
---

 

[rwsimon]

@Cobra, the EPA's MPGe rating on the car is about 115, as I recall. In any case, it takes about 4 kWh to charge the battery and you get around 15 miles for that. So the electric efficiency is around 3.75 miles/kWh. The MPGe rating is derived from converting kWh to the equivalent energy in gallons of gas. A gallon of gas provides about 32 kWh equivalent energy. So the EPA rating says the car goes a little less than 15 miles on a charge.

FYI, the efficiency of the Accord PHEV is rather good compared with other plug-in vehicles. Note that the battery pack is about 6.7 kWh capacity, but a chunk of that is essentially the "ordinary hybrid" battery. You can only put in about 4 kWh from the charger.

 

[Cobra]

FYI, the efficiency of the Accord PHEV is rather good compared with other plug-in vehicles.

Yes, all good info. My real point is that the car presently shows us MPG, and ignores electric use. How do we measure our electric efficiency? It's easy to say the Accord is good, but that's just the estimated electric efficiency (just like the window sticker MPG is an estimated gas efficiency.) Until there is an in car indication of kWh consumed over miles, you can't gauge your own electric efficiency locally. That would be nice to have on the Accord.

 

[rinthos]

My real point is that the car presently shows us MPG, and ignores electric use. How do we measure our electric efficiency? It's easy to say the Accord is good, but that's just the estimated electric efficiency (just like the window sticker MPG is an estimated gas efficiency.) Until there is an in car indication of kWh consumed over miles, you can't gauge your own electric efficiency locally. That would be nice to have on the Accord.

Actually it skews the data quite a bit, not sure if you noticed...but when driving in EV mode, MPG shows as "---" but as soon as you cut-over to gas, it's certainly averaging against the EV boost, because mine starts at 199MPG and works it's way down.

So in essence what you are seeing is a 'blended' rating..although without having any idea what they base the EV data on...we're a bit lost. So I agree, would be nice if Honda would make this data visible in more ways, and make it more meaningful.
---

 

[Cobra]

tually it skews the data quite a bit, not sure if you noticed...but when driving in EV mode, MPG shows as "---" but as soon as you cut-over to gas, it's certainly averaging against the EV boost, because mine starts at 199MPG and works it's way down.

So in essence what you are seeing is a 'blended' rating..although without having any idea what they base the EV data on...we're a bit lost. So I agree, would be nice if Honda would make this data visible in more ways, and make it more meaningful.
---

Haha, yeah, exactly. Electric miles are 'free' in the main MPG calculation. 200MPG is just like infinite MPG to the Accord calculation. Which I can understand, since it's a gasoline calculation... I'm just surprised the only electric number I can see on the car is EV range in miles (and that is an estimate as well.) Charge time or kWh in would be nice, so we could at least calculate energy usage.

 

[rwsimon]

It is true that there is no display of electrical efficiency. Given that the car switches between gas mode and electric mode for various reasons and at various times, I am not sure how one could even do that. The EV range display can go up while driving, stay constant for considerable distances (like while coasting), or drop quickly, so it isn't even accurate to take the original miles after charging and divide those by the 4 kWh it took to charge the car. It is a rather difficult problem, actually. I have a Kill-a-Watt meter on my charging outlet in the garage, so I keep track of how much electricity I actually dump into the car. ChargePoint clocks the kWh I use when I charge at their stations. So, if I really want to figure out exactly what is going on, I can take all those kWh used during a given tank of gas, multiply by 3.75 and then subtract that number from the total miles on the tank. That gives me the miles driven on gas which allows me to measure the real MPG for gas rather than the blended number given by the car's display. None of this is completely accurate, but it is one way to look at it. Personally, I'm happy enough with knowing that I am only filling up the tank every 800 miles or so. That works for me.