Decreasing Range of MG4

[T1 Terry]

Pot. Kettle. Black?

Our kettle is an Aldi special blue plastic cordless thing and our pots are all shiny, yet another strange thing .....

T1 Terry

 

[T1 Terry]

Some of those outliers are way out there. 570km on a full charge???? Downhill all the way with a tail wind for the whole distance????
How did you achieve that?

Even the run into Melbourne isn't 570kms, even though it's all down hill .... heading into a hole is generally like that .... maybe he was going round the outskirts, slowly working his way in, like one of those charity coin wishing wells .....

T1 Terry

 

[wattmatters]

Some of those outliers are way out there. 570km on a full charge???? Downhill all the way with a tail wind for the whole distance????
How did you achieve that?

It's a normalised range estimate, not an actual achieved range. So if the driving at that time had very good economy then the normalised 100% SOC range would correspondingly go up.

If we have a period with nothing much other than slow driving on our local roads (with 40-80 km/h speed limits) we can see range go up quite a bit.

As you note there are some "outliers" - whereas the majority of samples occur within a fairly tight band of economy rates with some bias overlayed due to seasonal impacts and to some extent the type of driving.

You can see a cluster of dots about halfway along the chart with poor economy and low normalised range - that was when we moved home and I was doing a lot of towing.

And there are other small clumps of dots with a low normalised range estimate - these would correspond with longer highway trips away from home.

 

[NerdBurger]

I have a near new MG4 77 and for city driving to work and back, it uses around 12kWh/100km (5.18mi/kWh).
Have done test runs on the highway where I've set the CC on various speeds and reset the counter at certain checkpoints whilst at speed to measure only driving efficiency at that speed. Sound system on, and aircon running at speed 7 to cool, with the car loaded up with holiday gear. Running in normal mode, high regen (default setting), tyres at dealer set 2.9bar. Also did runs up and back the highway to account for wind direction, and found:
1. At 101 km/h (62.8m/h), efficiency was 16.3 kWh/100km (3.8m/kWh) on average
2. At 105 km/h (65.2m/h), efficiency was 16.9 kWh/100km (3.7m/kWh)
3. At 111 km/h (69m/h), efficiency was 20.5 kWh/100km (3m/kWh)
4. The difference between driving into the wind (only 10knots) and with the wind was 0.8kWh/100km at each speed.

All done with outside temp at a perfect 25 degC.

So I figure that the time saved going the extra 6km/h above driving at 105km/h is not really worth it. Would not have thought the difference was so large without testing it. Anyone else found similar?

 

[decrep]

Haven't done your detailed test, but I guess it would come out similar.
I get around 12 in the burbs. and a mixed burbs freeway, 70, 110. 100, around 15, (drive from Mandurah to the Perth)
Similar temp around 25, but no ACC, A/C also on cool, regen on OPD

 

[NerdBurger]

Haven't done your detailed test, but I guess it would come out similar.
I get around 12 in the burbs. and a mixed burbs freeway, 70, 110. 100, around 15, (drive from Mandurah to the Perth)
Similar temp around 25, but no ACC, A/C also on cool, regen on OPD

Thanks decrep, BTW very jealous of you living in the windiest state in OZ.

Interestingly, have been looking at my usage, and things don't seem to add up. Last trip combo highway and town, was 14kWh/100 at 87km, and used 19% of charge. That would equate to 12.2kWh used for that 19%, which would give only 64kWh to 100% (for a 77 battery).
Does anyone know how the car calculates energy usage? Is it just like an amp meter? Is it accurate? Or is it just a case of the %age calculation GOM being off rather than the kWh measurement?

 

[decrep]

Thanks decrep, BTW very jealous of you living in the windiest state in OZ.

Yes It's great here, it's only a few kms to the surf or flat water.

Does anyone know how the car calculates energy usage? Is it just like an amp meter? Is it accurate? Or is it just a case of the %age calculation GOM being off rather than the kWh measurement?

I think this is an ongoing mystery. People that've had the car for a while, trust the GOM down to a few percent, but I'm nervous going much under 10% when doing the calibration

 

[ReintjeWA]

My mileage on the GOM varies a fair bit between charges, but the journey always uses up 20%. You’d think the range you get for a full battery would then also be pretty consistent, but I guess not.

 

[siteguru]

This was from my recent trip home from Alnmouth .. Purdey Lodge (Adderstone) services (Tesla top up to 85%) to home.

 

[Edd Beesley]

This was from my recent trip home from Alnmouth .. Purdey Lodge (Adderstone) services (Tesla top up to 85%) to home.

View attachment 46250

math says you have almost 4kwh left, you can do a few more miles!

 

[siteguru]

That was low enough for me to leave it for a while then do the <10 - 100% calibration charge.

I should have said .. that trip was at an average ambient temperature of about 8°C .. so in my mind the car hasn't noticeably lost any range in the 3.5 years I've had it.

 

[wattmatters]

3. At 111 km/h (69m/h), efficiency was 20.5 kWh/100km (3m/kWh)

I typically get between 16.5 and 18.5 kWh/100 km when driving the freeway between Coffs and Sydney at posted limits (mostly 110 km/h actual speed). The difference is usually wind and temperature conditions.

Would not have thought the difference was so large without testing it.

Air drag increases with the square of speed, and the power demand increases as a cube.

That 5 km/h extra speed over 105 km/h requires ~15% more power, ceteris paribus.

 

[NLMGSAN]

Don't forget the 77 kWh MG4 is heavier than the 64 kWh or 51 kWh versions.

 

[T1 Terry]

I have a near new MG4 77 and for city driving to work and back, it uses around 12kWh/100km (5.18mi/kWh).
Have done test runs on the highway where I've set the CC on various speeds and reset the counter at certain checkpoints whilst at speed to measure only driving efficiency at that speed. Sound system on, and aircon running at speed 7 to cool, with the car loaded up with holiday gear. Running in normal mode, high regen (default setting), tyres at dealer set 2.9bar. Also did runs up and back the highway to account for wind direction, and found:
1. At 101 km/h (62.8m/h), efficiency was 16.3 kWh/100km (3.8m/kWh) on average
2. At 105 km/h (65.2m/h), efficiency was 16.9 kWh/100km (3.7m/kWh)
3. At 111 km/h (69m/h), efficiency was 20.5 kWh/100km (3m/kWh)
4. The difference between driving into the wind (only 10knots) and with the wind was 0.8kWh/100km at each speed.

All done with outside temp at a perfect 25 degC.

So I figure that the time saved going the extra 6km/h above driving at 105km/h is not really worth it. Would not have thought the difference was so large without testing it. Anyone else found similar?

We live in Mannum South Australia, the trip to Adelaide return averages between 18.5kwh/100kms and 22kwh/100kms, depending on wind strength. The MG4 has a claimed 51kwh battery and claimed range of 405kms.
The Guessometer changes between the drive mode setting with the eco setting regularly predicting 320km range on a full charge, the longer trip is for my eye injections virtually at Adelaide Oval, roughly 210kms round trip and we get home, generally with 10% remaining, that would mean we had used 290kms of range .....

On one occasion, I left the Mt Barker Bunning and realised I had 18% of battery capacity remaining, yet travelled the 68 kms with 5% remaining when I got home, but I had a cramp in my right leg from holding the boot off the accelerator That means, even though it was still expressway and back road with the mandatory stop signs and corners, I must have used around 10.5kwh/100kms .....

The GOM is just that, a Guessometer, multiply by the date and divide by the page number and in a variable factor called mood on the day, one for the driver and one for the car

T1 Terry

 

[wattmatters]

Don't forget the 77 kWh MG4 is heavier than the 64 kWh or 51 kWh versions.

The posted economy rate specs have the 77 at a little over 1% higher consumption per km than the 64.

 

[NLMGSAN]

163 datasets of the 51, 64 and 77kW versions of the MG4 with weighted averages based on total milage reported, and split using summer and winter periods.

The source is German website.
Note: I had the upper and lower extremes in the summer period removed to reduce the effect of outliers.