Mercedes A-Class Forum banner

21 - 25 of 25 Posts

Registered
Joined
320 Posts
The figures it gives are simply the amount of fuel/electricity used over the entire distance regardless of what has actually driven the car. Thats why MPG is quoted as 256 ;)
 

Registered
Joined
24 Posts
Hi,
I have had my a250e for just a few weeks. I came across this discussion when trying to work out how Mercedes Me calculates MPG and MpkWh. Yesterday my journey was 177 miles, mostly on motorway. I started with a full battery and at outset it said I had a range of 32 miles on battery - I understand this will be a guesstimate based on previous usage but also environmental conditions such as temperature. I thought I would try the 'route based operating mode strategy' and set the sat nav for a return journey (as I could not recharge en route) and selected eco mode. So I thought the system would look at the whole return route and work out when to use full electric (up to 32 miles) and petrol to get the most economical journey overall. Having arrived home and looked at the Mercedes Me trip details it tells me I have travelled 177 miles, 68 in electric only, MPG is 67, mpkWh is 18.8. I am assuming MPG is calculated on the whole journey with electric and petrol combined so pro rata this works out at 41 mpg while just on petrol. 41 mpg seems low as I was cruising on the motorway most of the journey so I was wondering if part of the petrol consumption was taken up by recharging the battery which achieved 68 miles fully electric out of 177 - when it projected I would get just 32 miles fully electric before I set off (and the maximum stated by Mercedes is 44 miles). I concluded that the battery must have recharged to an extent over the journey. Obviously this would cost in terms of petrol usage to recharge (and explain the very average 41mpg on petrol only) but I presume that the Mercedes analytics system works out that the electric generated will be more beneficial in the whole journey than the cost of the petrol consumed to recharge.
I have read here that there is little recharging of the battery during the journey but my experience yesterday doesn't seem to be consistent with this. I have not found anything on the Mercedes website to explain how the figures in the Mercedes Me trip data are calculated. Have I misunderstood something here? 馃
I also see the same kind of regen that you do which is excellent. The figures you're seeing for the mpg seem odd though. What mine "seems" to do is base the mpg off how much fuel is used overall, including electric miles which then gives you a much higher figure.

I have seen the app take a while to update the figures completely though. Try force closing the app and reopening.
 

Registered
Joined
3 Posts
The figures it gives are simply the amount of fuel/electricity used over the entire distance regardless of what has actually driven the car. Thats why MPG is quoted as 256 ;)
Thanks. Yes, 256 mpg is a nice 'headline' for promotion 馃槒 and I understand it is an overall figure for a range of typical usage in petrol and electric combined. However, I cannot understand the 68 miles on full electric unless there is significant regen during the journey (albeit at the cost of more petrol). Or is it really possible to get 68 miles full electric on a single charge if the conditions are right? If it was the latter, I would have expected the electric range figure to change in the display during the journey. During yesterday's journey the range started at 32 and gradually reduced (I only once noticed it increase, by 1 mile, before reducing again), at the end of my journey it showed a range of 1 mile remaining. I may be misunderstanding the Mercedes Me app figures but it ought to be easy to interpret for the general user and also to have some clear explanation in the Mercedes literature unless the intention is to make it deliberately opaque 馃
 

Registered
Joined
3 Posts
I also see the same kind of regen that you do which is excellent. The figures you're seeing for the mpg seem odd though. What mine "seems" to do is base the mpg off how much fuel is used overall, including electric miles which then gives you a much higher figure.

I have seen the app take a while to update the figures completely though. Try force closing the app and reopening.
Thanks. Yes, you're right. I am also expecting the estimated electric range to increase over time as the car 'learns' that it can get more than 32 miles on electric (it will probably also increase the estimated range as the weather warms up). As I expressed in an earlier response to this, it would be nice to have a lay person explanation of how it all works in the Mercedes literature but I haven't found it yet! 馃槉
 

Registered
Joined
24 Posts
Thanks. Yes, you're right. I am also expecting the estimated electric range to increase over time as the car 'learns' that it can get more than 32 miles on electric (it will probably also increase the estimated range as the weather warms up). As I expressed in an earlier response to this, it would be nice to have a lay person explanation of how it all works in the Mercedes literature but I haven't found it yet! 馃槉
The estimated electric range is electric only and assumes that you won't use the ICE at all. Therefore if you run it purely on EL mode that is what you will get (roughly). I find my electric range estimate to be pretty accurate. It usually gives me a figure of 35-40 miles which I regularly achieve.

The mpg figure is also accurate albeit somewhat misleading. It basically writes off the cost of electricity and gives you a figure based on how many miles you travelled using petrol regardless of whether you used electric or not.

Say you travel 50 miles but some miles were done on electric it would give you a figure based on how many gallons of petrol were used regardless of how much electricity was used.

Example -
50 miles travelled
5 miles on petrol
45 miles on electric
1 litre of petrol used
Reported consumption - 227 mpg
 
21 - 25 of 25 Posts
Top