Miles / kWh VS Real Range

[SKA]

Hi all. Have the car (SR) for almost a year now so have been through the hot and cold weather. I fully understand that the range differs a fair bit between temperature. So off the guessometer if I get 4miles / kWh in summer, I am not surprised to get 3 or less in winter. I get that.

However it bugs me that the miles/kWh on a trip does not match the range or the distance i have travelled. For example, this morning I charged to 100% , reset the trip computer . Travelled 60 miles, achieving 4 miles / kWh according to the computer, which should equate to 15kwh used and on a 50kwh battery I worked it out as 33.33% . However when I arrived, the 60 mile tried has used 42% .

Am I missing something ? Or is it just me? I thought I get higher and lower miles/kWh reading according to temperature but not a same reading but I need to factor it in myself.

Same for you guys or is it just me ?

Thanks

 

[drmcw]

I'm guessing here, but I think that the battery % will come from the BMS and hopefully the miles per kWh will be based off of the power delivered. In that case the miles per kWh should be a better metric and the reason that your battery % is out of kilter is that you have the SR and the flat voltage curve of the LFP battery pack means that the BMS cannot calculate an accurate %.

 

[Nikkwarn55]

Hi all. Have the car (SR) for almost a year now so have been through the hot and cold weather. I fully understand that the range differs a fair bit between temperature. So off the guessometer if I get 4miles / kWh in summer, I am not surprised to get 3 or less in winter. I get that.

However it bugs me that the miles/kWh on a trip does not match the range or the distance i have travelled. For example, this morning I charged to 100% , reset the trip computer . Travelled 60 miles, achieving 4 miles / kWh according to the computer, which should equate to 15kwh used and on a 50kwh battery I worked it out as 33.33% . However when I arrived, the 60 mile tried has used 42% .

Am I missing something ? Or is it just me? I thought I get higher and lower miles/kWh reading according to temperature but not a same reading but I need to factor it in myself.

Same for you guys or is it just me ?

Thanks

Hi SKA, I have never done so much maths ever, as when i got my MG4. I can never get the car read out to match the % and the miles done. So there something not quiet right in calculation of the cars computer. Who would know the truth of this.... But I still love the car though and very much enjoying it.

 

[N2STY]

However it bugs me that the miles/kWh on a trip does not match the range or the distance i have travelled. For example, this morning I charged to 100% , reset the trip computer . Travelled 60 miles, achieving 4 miles / kWh according to the computer, which should equate to 15kwh used and on a 50kwh battery I worked it out as 33.33% . However when I arrived, the 60 mile tried has used 42% .

Don't reset the trip counter give the computer a chance to learn your driving and then the gom will be more accurate

 

[Bodgerx]

Hi all. Have the car (SR) for almost a year now so have been through the hot and cold weather. I fully understand that the range differs a fair bit between temperature. So off the guessometer if I get 4miles / kWh in summer, I am not surprised to get 3 or less in winter. I get that.

However it bugs me that the miles/kWh on a trip does not match the range or the distance i have travelled. For example, this morning I charged to 100% , reset the trip computer . Travelled 60 miles, achieving 4 miles / kWh according to the computer, which should equate to 15kwh used and on a 50kwh battery I worked it out as 33.33% . However when I arrived, the 60 mile tried has used 42% .

Am I missing something ? Or is it just me? I thought I get higher and lower miles/kWh reading according to temperature but not a same reading but I need to factor it in myself.

Same for you guys or is it just me ?

Thanks

I have the same car/battery.

It's a combination of average to poor efficiency, LFP based battery and a GOM that isn't the most consistent.

I'm just trying to forget about it. Pay as much or as little as miles left gauge on a ICE car.

I rely more on batt percentage and just have a rough plan of when/where to charge on a longer trip.

 

[Nikkwarn55]

Don't reset the trip counter give the computer a chance to learn your driving and then the gom will be more accurate

Ok will let it get up to a thousand miles and see if it gets better, cheers.

 

[TheArcher]

While I am waiting for my MG, my Smurf is consistently giving me 3.9m/kWh. That's good enough guide for me to check consumption. It is what it is.

 

[SKA]

Does the m/kWh figures that you guys got "corresponds " with the actual mileage covered / battery percentage. I tend not to use range Vs percentage as this hugely differs against the m/kWh. I understand the GOM and I know it's a guess work prediction but what I am talking about here is the actual mileage covered from full charge against the m/kWh so there is nothing to predict but to show the fact recorded.

Say from 100% full charge you get 4m/kWh and had travelled 100 miles on a trip or since reset, is the the remaining battery 50%? (On a 50kwh SR)

Mine doesn't, so not sure if this is "normal" or mine needs attention. (As my other EV , the m/kWh against distance travelled is spot on, or pretty damn close if factoring in the decimals we don't get in the %)

Thanks all.

 

[N2STY]

After about 2or3k miles mine is pretty good if I am doing a longer journeys I normally beat the gom but I would rather have it that way so I don't get caught short (LR)

 

[Gadget Geek]

Does the m/kWh figures that you guys got "corresponds " with the actual mileage covered / battery percentage. I tend not to use range Vs percentage as this hugely differs against the m/kWh. I understand the GOM and I know it's a guess work prediction but what I am talking about here is the actual mileage covered from full charge against the m/kWh so there is nothing to predict but to show the fact recorded.

Say from 100% full charge you get 4m/kWh and had travelled 100 miles on a trip or since reset, is the the remaining battery 50%? (On a 50kwh SR)

Mine doesn't, so not sure if this is "normal" or mine needs attention. (As my other EV , the m/kWh against distance travelled is spot on, or pretty damn close if factoring in the decimals we don't get in the %)

Thanks all.

When I do a long journey, I look at the distance to be covered on the sat-nav (Google maps on Android Auto) and the predicted range on the GOM. I then subtract one from the other and get the miles remaining I should get at journeys end. When travelling I see this figure change as I go uphill, along the flat, and down a slope.

The average m/kWh is just that, an average. If you finish your journey travelling up hill, it may not represent the whole of the journey which may have been on the flat, and finishing on a down hill will give an apparent impressive performance.

Edit: I think I may have just spotted your problem . . . Regenerative deceleration. I have just made a journey to pick up a family memeber and it was mostly uphill there. The m/kWh was 2.1. Coming back, I noticed regen made a significant difference to the average, arriving with 2.9 m/kWh. Therefore, through your journey you are going to be depleting and replenising the battery as you go.

 

[Nikkwarn55]

While I am waiting for my MG, my Smurf is consistently giving me 3.9m/kWh. That's good enough guide for me to check consumption. It is what it is.

hi Archer, great your getting 3.9m/kw out of this little chappy , so funny.
hope your new Mg4 comes soon and gives you all the pleasure mine has given, great ev .

 

[Tim Green]

In my gen1 I try to get at least 3.6 m/kw which I find will generally match the GOM to the actual, but over the whole battery capacity. I do not think it is a linear decay so you cannot actually say 50% should be 82 miles. (Half of 164).
Also I keep a beady eye on the GOM compared to satnav distance to go and slowing down to say 50 mph makes a huge difference if battery is running a bit low.

 

[profdraper]

Hi all. Have the car (SR) for almost a year now so have been through the hot and cold weather. I fully understand that the range differs a fair bit between temperature. So off the guessometer if I get 4miles / kWh in summer, I am not surprised to get 3 or less in winter. I get that.

However it bugs me that the miles/kWh on a trip does not match the range or the distance i have travelled. For example, this morning I charged to 100% , reset the trip computer . Travelled 60 miles, achieving 4 miles / kWh according to the computer, which should equate to 15kwh used and on a 50kwh battery I worked it out as 33.33% . However when I arrived, the 60 mile tried has used 42% .

Am I missing something ? Or is it just me? I thought I get higher and lower miles/kWh reading according to temperature but not a same reading but I need to factor it in myself.

WLTP as 'guessometer' (most EVs, really); good description. Based in the Netherlands, this database may be of use, much ongoing work being done here about this & other common EV issues: EV Database

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So in realtion to the MG ZS EV standard range specifically, their data on range shows:

Real Range Estimation between 185 - 405 km​

City - Cold Weather *	275 km
Highway - Cold Weather *	185 km
Combined - Cold Weather *	225 km

City - Mild Weather *	405 km
Highway - Mild Weather *	240 km
Combined - Mild Weather *	305 km

Indication of real-world range in several situations. Cold weather: 'worst-case' based on -10°C and use of heating. Mild weather: 'best-case' based on 23°C and no use of A/C. For 'Highway' figures a constant speed of 110 km/h is assumed. The actual range will depend on speed, style of driving, weather and route conditions.

MG ZS EV Standard Range

All details and specs of the MG ZS EV Standard Range (2021). Compare price, lease, real-world range and consumption of every electric vehicle.

ev-database.org

 

[okohll]

I've been thinking about this too. Firstly let me say I'm not too worried - as people have said, using the % and estimated range left is fine for driving purposes. I'd just like to know out of intellectual curiosity how the calculation is done.

From All-New MG4 EV | Fully Electric Hatchback

*Range applies to All-New MG4 EV SE Long Range with the 64kWh battery from a single charge on the WLTP combined cycle: Combined Range 281 miles (450 km): City Range: 360 miles (579 km); Combined Driving Efficiency: 3.8 miles/kWh (16.0 kWh/I00km)

Now 281 / 3.8 ~= 74, so you'd need a 74kWh battery to get that range at that efficiency.

Of course, a lot depends on driving style, temperature etc., but the figures above "combined range" and "combined driving efficiency" are from the same WLTP test so you have to assume they are consistent with each other at least.

The only thing I can think is that they're measuring energy put into the battery, not energy stored by it, i.e. there is transfer inefficiency. 74 / 64 = 1.16, or actually to be more accurate, using the usable capacity of 61.7 (from ev-database.org), the ratio is 1.2, i.e. there's about 20% loss during charging, which doesn't sound unreasonable especially if fast charging.

You could do some tests, i.e. discharge to zero, charge to 100% measuring the energy your charger reports, discharge again to zero and see what range you get and what efficiency the car reports over the trip. Personally as above I'm not bothered enough to drive up and down my road until it runs out though.

If anyone else is though, it would be interesting to see whether the calculated efficiency the car reports is taking into account (estimated) input losses.

 

[Susanna]

Maybe they are including a fair amount of regen into the equation? The city range at 360 miles must include a huge amount of regen!

 

[okohll]

Maybe they are including a fair amount of regen into the equation? The city range at 360 miles must include a huge amount of regen!

Maybe, but the m/kWh and range should still be consistent with each other. Funnily enough, in my short time driving it, I've found long distances to be better efficiency than driving in town, so am not going get anywhere near that range under any circumstances.

 

[Ruislip Resident]

Maybe, but the m/kWh and range should still be consistent with each other. Funnily enough, in my short time driving it, I've found long distances to be better efficiency than driving in town, so am not going get anywhere near that range under any circumstances.

I think it might be to do with HV Battery heating up as it gets used. Currently on short trips I often start at just 3 miles per KWH but after a few miles eg maybe 3 it creeps up to just below or just over 4. On longer runs ( on not very cold days) it can get up to 5 [I drive in Eco with very little heating on as I've got used to it like that with no discomfort].