At 18000 miles over the past 10 months, I have one of the higher mileage W214 E53s on the road. The stats reported in the app Trip Data “From Reset” section are as follows:

- Distance Traveled: 18008 miles
- Electric Driving Ratio: 47%
- Fuel: 46.0 mpg
- Electric: 5.9 mpkWh

The actual mpg and mpkWh can be approximated by estimating the actual miles driven in each mode.

53% of 18008 equals 9544 gas powered miles. The remaining 47%, or 8464 miles, is the estimated amount driven on the HV battery.

18008 miles divided by 46.0 mpg equals 391.5 gallons of fuel. Dividing the 9544 miles by 391.5 gallons equals 24.4 mpg which is reasonable when compared to the combined EPA 23 mpg estimate shown on the window sticker.

18008 miles divided by 5.9 mpkWh equals 3052 kWh. Dividing the 8464 miles 3052 kWh indicates an average 2.77 mpkWh. This is somewhat surprising since driving locally in EL mode, mostly in 4th gear, usually reports an mpkWh between 1.6 and 2.5 driving depending upon the temperature. I think the higher than expected mpkWh for battery powered miles can be attributed to some kWh added by recuperation as well as a portion of the electrical miles being driven in 7th, 8th, and 9th gears.

Most of the HV battery charging occurred at home and at hotel destination chargers. Very little charging was done at DC chargers since the cost per kWh is more than the cost of gasoline per mile. The inability to charge the E53 at non-MagicDock Tesla Superchargers also factored into the minimal amount of DC charging while on road trips in lesser traveled areas not serviced by EA.

 

Really great numbers - thanks for the details. I'm on the opposite side of miles as you so it's very insightful.

 

I think there is a valid reason why the EV miles seem worse and the gas miles seem better. The math does not account for all the idle time when in gas mode, ie. even during the gas driven miles the idle time at red lights and aux consumption while waiting in the car etc. will use electric power. So the EV usage has 18k miles worth of idling in it while the gas miles have none, it merely has the miles driven on fuel as if you never came to a complete stop and sat the car idle.

Regardless of this, I think the numbers are really decent. I just drove my Audi RS etron GT on a long distance trip and averaged 2.5 mile/kWh (I prefer to use the 40 kWh/100 mile representation) so yours is very much in line with that. I can get it much closer to 3.3 mile/kWh in the spring and when I only drive city streets at low speed and not highway at 85 mph.

My daughter's GLC 350e has 507 mpg and 2.5 mpkWh over 4,100 miles since reset at 95% EV ratio. BTW to get the proper values you don't need to do all that mileage math, just multiply the MPG values with the percentage ie. 46 mpg * 53% = 24.38 mpg in your case. In my daughter's case it comes out to 2.375 mpkWh and 25.35 mpg which makes sense, she sure loves to sit in her car and chat with her friends ;-).

I am almost 100% certain that with the proper adapter you can charge the E53 at the Tesla superchargers. I just charged my Audi at one without zero issues other than it was significantly slower than the ChargePoint 400 kW charger I tried next.

As for the pricing, I'm also not 100% sold that you're correct, certainly not everywhere and all the time. If we assume 2.5 mpKwh to drive 100 miles you'd need 40 kWh which at $0.44/kWh would be $17.60 for 100 miles. If we assume 24 mpg, you'd need 4.17 gallons to drive 100 miles which means as long as gas is more expensive than $4.22/gallon EV will be cheaper. I also have a strong feeling that EV DC charger prices are set where they are to produce parity with gasoline. If it was more people would opt to drive their gas cars. If it was less, charging stations would fail to maximize profits. Once EV/PHEV becomes more mainstream pricing will be driven by supply/demand even more and will have no real bearing on what the actual price of electricity is.

I get free electricity at night and I have solar during the day so for me it's all free, but trust me, I don't drive EV/PHEV for the cost saving. It's all about convenience and performance.

 

I don't agree that idle time at stop lights adversely impacts mpkWh since it is a measure of distance per unit of power not time.

I am 100% certain that the W214 E53 cannot be charged at non-MagicDock Superchargers. I use the Tesla brand adapter which is essentially the same one incorporated into MagicDock. The E53 charges fine at MagicDock chargers, but will not work at the regular Superchargers with an adapter. There are no MB PHEVs in the list of MB cars in the Tesla phone app. As recent as a year ago I was able to charge my EQS SUV at Superchargers with my adapter by indicating that it was a Ford F150 Lightning. That hack does not work with the E53.

Here in the Northeast I am paying $3.60 for premium and the cost for DC charging ranges between $0.52 and $0.65 per kWh. Whether or not it's cheaper to run in EL mode on DC charges clearly depends upon where you live.

 

Idle time at stop lights continues to use power unless one isn't using aux equipment such as HVAC, lights or entertainment equipment.
Where I live AC is used 10 months per year and a red light cycle is typically 3 to 5 minutes. My one mile trip for groceries is 2 minutes driving and 8 to 10 minutes stopped at red lights.

I just asked my neighbor and she said that she charges her EQ E320 at a nearby Tesla supercharger without using an adapter. AFAIK all MY-25 and newer electric MB's have a Tesla compatible NACS port.

 

Maybe I should have said, "I don't agree that idle time at stop lights significantly adversely impacts mpkWh..."

In my case, relatively little time has been spent at stop lights over the last 18000 miles.

Besides, doesn't the aux equipment run off the 12v battery? And isn't the 12v battery mostly charged by the electric motor acting as a generator?

 

I wish they could have separate stats for gas engine and battery motor - so you don't need to do the math on your own.

 

The W214 E53 has a CCS port for DC charging and a J1772 port for AC charging. According to the specifications shown on MBUSA.com, the EQE 320 has the same ports as the E53. Perhaps your neighbor is charging at a Tesla Supercharger equipped with MagicDock.

 

https://www.mbusa.com/en/charge/nacs-charging

The site does not differentiate between EV and PHEV options here, and it really shouldn't. That adapter on the site looks identical to what I bought for my Audi etron and to the one my buddy got for his Ford F150 Lightning and incidentally to the Lectron adapter. I suspoect they all come from the same factory with different branding screen printed/etched onto them.

For fun I'll take my daughter's PHEV out ant see if I can charge it at a Tesla charger but based on the info I don't see why I shouldn't be able to.

 

I don't know if she has an adapter. Her car came with a Mercedes Flex Cable for home use.
Per the MB website:

 

I have not tried a Supercharger since I got the MBUX E333.8-58 update. Perhaps that will make a difference. Please let us know which car you specify in the Tesla app when you try an adapter with the GLC PHEV.

The last time I used a MagicDock equipped Supercharger I initiated the session from the dashboard not the Tesla app. This works because the Navigation system knows about the MagicDock Supercharger locations but not the regular Tesla Superchargers.

 

I tried this morning at a regular Supercharger with the Audi branded NACS to CCS on my daughter's car and I failed to charge. Looks like MB PHEVs are not ready to use the Tesla superchargers.