Mileage discrepancy between car and App

[Weeble]

This was discussed on the MG4 forum a while ago, but I thought I'd bring it up again here on the chance that someone knows if any MGS5 software changes might explain things.

I've had the car for exactly 2 months and done almost 700 miles (so, yes a low mileage user). I had to go away for the week last week so gave the battery a 100% charge to avoid having to use public chargers and noticed that the Range shown in the car was 2 miles less than that shown on the ISmart app..
Yesterday I had to make another longish trip of estimated 180+ miles so I did another 100% charge and the Range was 7 miles less than shown on the app.
Last night I charged to 80% and this morning the Range was a full 10 miles less than shown on the app.

I appreciate that the Range shown in the car is dynamic, depending on various load factors, but my driving style was fairly constant as was the type of road mixture. So, does anyone have any theories as to why this discrepancy has an increasing trend?
Until now, I assumed that the app just read the Range value from the car, but it obviously has its own algorithm.

 

[Amun]

I suspect that the app is reporting calculated mileage using the most economical setting.
My MG5 would show the Eco mode range in the app, but it defaulted to Comfort mode in the car - so they never matched. I haven't checked on the S5 yet, though.

 

[Lovemyev]

The ZS EV sometimes displays a mismatch in range also on times.
I have seen a slightly difference range report between what is shown in the instrument cluster, to what is shown on the screen of the head it of the car.
What’s that all about !.
Some type of a lag / glitch between each of the units I suspect because as soon as the car starts to move, they both realign again.
Not seen a 10 mile differential though TBF.

 

[rpannell]

Most likely, the fan was turned on in the car. This is unknown to the app so the app gives a higher potential mileage than the car. Also, as others have said it can be a difference in the driving mode selected

 

[barry7153]

On a similar thread. Usually a very low mileage driver (3000 miles a year) so usually no range anxiety. However I travel 250 MLS to visit Mum a few times. This time planned to recharge at 220ml after starting on 100%. Right from the start MLS/KW was showing 2.2 though did slowly creep up to 3.4. Most of the trip is on motorway/ duel carriage, so in cruise control (65ml/HR) most of the time. Even turning off the AC, it was freezing that day, and radio seemed to make no difference to the ml/kWh and predicted range which gradually got worse throughout the trip, adding to the range anxiety. In the end I had to recharge at 210 with just 10 MLS remaining in the battery. I suppose my question is why when driving with no extras switched on and in cruise control is the mls/KW and range prediction still so random?

 

[rpannell]

On a similar thread. Usually a very low mileage driver (3000 miles a year) so usually no range anxiety. However I travel 250 MLS to visit Mum a few times. This time planned to recharge at 220ml after starting on 100%. Right from the start MLS/KW was showing 2.2 though did slowly creep up to 3.4. Most of the trip is on motorway/ duel carriage, so in cruise control (65ml/HR) most of the time. Even turning off the AC, it was freezing that day, and radio seemed to make no difference to the ml/kWh and predicted range which gradually got worse throughout the trip, adding to the range anxiety. In the end I had to recharge at 210 with just 10 MLS remaining in the battery. I suppose my question is why when driving with no extras switched on and in cruise control is the mls/KW and range prediction still so random?

It's not the road speed that's important to efficiency but the air speed. So perhaps there was a strong Northerly wind on that trip? Also dry cold air is more dense than damp warm air so perhaps a cold day. These things also affect petrol cars but because the petrol engine is so inefficient, the overall efficient needle is barely moved with a petrol car due to weather reasons.