Consumption

[carmelo]

I'm reaching out for insights or potential solutions to an issue I'm experiencing with my MG4. Initially, the car was performing efficiently at 15.5 kWh/100km (approx. 4 miles/kWh). However, following a fault and subsequent replacement of the AC compressor, I've noticed a significant increase in consumption to 21.5 kWh/100km (roughly 2.96 miles/kWh).
I returned the vehicle to the dealership for a check-up. They had it over a weekend and assured me that everything was functioning correctly. However, the increased consumption persists. I'm certain that my driving habits and the weather conditions have remained consistent throughout this period.
Has anyone here faced a similar issue after servicing or replacing parts? Any advice on how to address this unexpected rise in energy consumption would be greatly appreciated.

Thank you in advance for your help.
Best regards,
Carmelo

 

[Rolfe]

You should be getting far better than that in Malta, certainly.

 

[jimmie8521]

I bought a new MG4 long rage back in September and initially I was getting 3.5 miles per kWh but currently I’m down at 2.7. I put that down to the fact that all the electrics are getting used more in the winter months but it still seems a big percentage reduction.

 

[Rolfe]

Yes, @jimmie8521, that's pretty much par for the course at these latitudes. It has a lot to do with the change in battery performance in colder weather. But I'm concerned about what @carmelo is seeing, because as far as I know it's still warm enough in Malta that he should be seeing well over 3 miles/kWh.

 

[Alb]

It's around 17°C in Valletta at the moment.

 

[Rolfe]

I rest my case. That's like high summer where I live.

 

[carmelo]

Thanks for all your input and feedback.
I wish I can nail the cause of the added consumption (or lower efficiency) being experienced.

 

[Robf]

Thanks for all your input and feedback.
I wish I can nail the cause of the added consumption (or lower efficiency) being experienced.

Just checking that you have turned off intelligent battery heating?

 

[carmelo]

Yes, it was never on.

 

[Rolfe]

I think you may need to go back to your dealer and get more insistent with them. This is not right.

 

[carmelo]

I agree. They convinced me to test for another couple of weeks.
They also told me that I should charge the battery to 100% once a month, and they insisted even though I pointed out that the manual advices to charge up to 80% as much as possible.

Probably trying to find a reason why my 5000km vehicle has changed consumption rate drastically at 3500km right after the AC compressor replacement.

Let's see what the future will bring to this issue.

 

[Chequers]

Have you ever done a balance charge ?

 

[carmelo]

I only charge the vehicle using a 7KW charger. I charge it whenever the battery charge level is at or around 40% and charge it up to 80%

I thought that this method was balance charging the battery.

 

[Robf]

I only charge the vehicle using a 7KW charger. I charge it whenever the battery charge level is at or around 40% and charge it up to 80%

I thought that this method was balance charging the battery.

No, You have to charge to 100% and then it starts to balance, leave it plugged in for a few hours whilst balancing the cells as it does take more electricity

 

[Rolfe]

This could be it, Carmelo. Generally speaking you don't want to charge the car up to 100% unless you need the range - which seems unlikely in Malta. But about once a month you should charge up to 100% on an AC charger and then let the car sit until it's no longer drawing any power and the app is showing that the car is no longer charging. That's a balance charge. You should then try to drive the battery down to under 80% again as soon as is reasonably practical.

What concerns me is that you first saw the issue rather suddenly after the car had been in at the dealer's. But maybe that's coincidence. Give it a proper balance charge or two and see what happens.

Also, it's good every three to six months to do a long AC charge from under 10% battery right up to 100% and balance. If you've had your car for six months or more you should maybe try doing this.

Some people say the car can balance to some extent at 80% but this is debatable and in any case it's not a full balance charge.

 

[carmelo]

This could be it, Carmelo. Generally speaking you don't want to charge the car up to 100% unless you need the range - which seems unlikely in Malta. But about once a month you should charge up to 100% on an AC charger and then let the car sit until it's no longer drawing any power and the app is showing that the car is no longer charging. That's a balance charge. You should then try to drive the battery down to under 80% again as soon as is reasonably practical.

What concerns me is that you first saw the issue rather suddenly after the car had been in at the dealer's. But maybe that's coincidence. Give it a proper balance charge or two and see what happens.

Also, it's good every three to six months to do a long AC charge from under 10% battery right up to 100% and balance. If you've had your car for six months or more you should maybe try doing this.

Some people say the car can balance to some extent at 80% but this is debatable and in any case it's not a full balance charge.

Thanks Rolfe,
I charged the car to 100% and left it until the charger stopped (as you suggested).
Drove around, and indeed the consumption returned to normal

Thanks for all your help and suggestions.

 

[ukslim]

Well, that's a lesson for us all.

I find it a little disappointing that we have the chore of managing a balancing schedule. Oh well; I guess my next EV will have fixed it.

 

[Rolfe]

I don't think it's much of a chore, really. I have an SR with the LFP battery and I just let it go to 100% and balance every time I charge. It's just not an issue. But people with the NMC battery have laughed off my suggestion that the LFP is easier to manage because of that. They just remember to take off the 80% limit for one charge every few weeks.

 

[siteguru]

... whereas we don't have to remember to do anything (other than actually charge).

 

[Rolfe]

Well, yes, but some LR owners get a little touchy about this.

(I do remember to do a full charge from below 10% now and again. Successfully accomplished last week, so that's that out of the way for a few months.)