MG4 Range

[amdmad]

It's a shame that the app doesn't remember any journeys the car drives,like the Nissan Leaf

 

[Macadoodle]

I'm beginning to think LFP packs are extremely hobbled by the cold. Took the dog to his favourite woodland walk today, around 8 miles from my house , meandering B road, passing through a couple of villages.
Stuck on 2 m kWh the whole way, didn't use any heating save for a 2 minute windscreen demist, temp was 4 degrees.
On the way home, trip had reset itself but noticed m/ kWh suddenly rocketing, again no heating and temp still 4 degrees.
I can only imagine the internal resistance of the pack destroys efficiency when you first set out, but with the car resting during the dog walk, the heat spread through the pack and it 'woke up'

I did have the aero drag of a wet standard poodle noggin sticking out the rear window, so I could have got closer to 5m kWh perhaps

 

[Ian Key]

I'm beginning to think LFP packs are extremely hobbled by the cold. Took the dog to his favourite woodland walk today, around 8 miles from my house , meandering B road, passing through a couple of villages.
Stuck on 2 m kWh the whole way, didn't use any heating save for a 2 minute windscreen demist, temp was 4 degrees.
On the way home, trip had reset itself but noticed m/ kWh suddenly rocketing, again no heating and temp still 4 degrees.
I can only imagine the internal resistance of the pack destroys efficiency when you first set out, but with the car resting during the dog walk, the heat spread through the pack and it 'woke up'

I did have the aero drag of a wet standard poodle noggin sticking out the rear window, so I could have got closer to 5m kWh perhaps

Someone on Facebook posted that they found the battery heating was switched on after a software update.

 

[Ayoull]

I'm beginning to think LFP packs are extremely hobbled by the cold. Took the dog to his favourite woodland walk today, around 8 miles from my house , meandering B road, passing through a couple of villages.
Stuck on 2 m kWh the whole way, didn't use any heating save for a 2 minute windscreen demist, temp was 4 degrees.
On the way home, trip had reset itself but noticed m/ kWh suddenly rocketing, again no heating and temp still 4 degrees.
I can only imagine the internal resistance of the pack destroys efficiency when you first set out, but with the car resting during the dog walk, the heat spread through the pack and it 'woke up'

I did have the aero drag of a wet standard poodle noggin sticking out the rear window, so I could have got closer to 5m kWh perhaps

LFP cells do not show any major degradation in performance until around -10C to -20C, it is cold mechanical and moving components as well as things such as reduction gearbox oil will be highly viscous until it reaches optimal temperature, that decreases performance.

Also due to increased rolling resistance which increases energy required for same work done and air density due to cold ambient temperature, which increases drag, this coupled with heating requirements for comfort reduce winter performance.

The battery is actually impacting very little until you get to the extreme temperatures.

 

[Macadoodle]

LFP cells do not show any major degradation in performance until around -10C to -20C, it is cold mechanical and moving components as well as things such as reduction gearbox oil will be highly viscous until it reaches optimal temperature, that decreases performance.

Also due to increased rolling resistance which increases energy required for same work done and air density due to cold ambient temperature, which increases drag, this coupled with heating requirements for comfort reduce winter performance.

The battery is actually impacting very little until you get to the extreme temperatures.

2 m kWh on the 8 miles out compared to 4.7 on return though, can't see thicker gear oil having that much effect, there's probably little in there as I have 'the leak '
Be interested if long range owners are noticing such a marked difference, ternary cells are much more flexible temp wise by all accounts.
Nope, I've a sneaking suspicion I chose the wrong pack for north Scotland, sell the car or move to spain methinks.

 

[MoDolph]

2 m kWh on the 8 miles out compared to 4.7 on return though, can't see thicker gear oil having that much effect, there's probably little in there as I have 'the leak '
Be interested if long range owners are noticing such a marked difference, ternary cells are much more flexible temp wise by all accounts.
Nope, I've a sneaking suspicion I chose the wrong pack for north Scotland, sell the car or move to spain methinks.

Ours is the long range and it seems to randomly sometimes have really bad consumption for the first few miles. Our return trip today took ages to go above 2m/kWh even though it was country lanes at 30-40mph. The battery must have been hot after a long motorway blast and short rapid charge.

It must be the heater but I can't believe it can be that bad.

 

[Cocijo]

I'm beginning to think LFP packs are extremely hobbled by the cold. Took the dog to his favourite woodland walk today, around 8 miles from my house , meandering B road, passing through a couple of villages.
Stuck on 2 m kWh the whole way, didn't use any heating save for a 2 minute windscreen demist, temp was 4 degrees.
On the way home, trip had reset itself but noticed m/ kWh suddenly rocketing, again no heating and temp still 4 degrees.
I can only imagine the internal resistance of the pack destroys efficiency when you first set out, but with the car resting during the dog walk, the heat spread through the pack and it 'woke up'

I did have the aero drag of a wet standard poodle noggin sticking out the rear window, so I could have got closer to 5m kWh perhaps

They are interesting observations. Perhaps the chemistry of this pack does need to be at a certain temperature to perform well, more so than other types of HV batteries.
I know others have said that it shouldn’t, but I can’t think of another explanation. Also, MG seem to have added battery warming technology to the cars with this pack chemistry.

 

[Macadoodle]

They are interesting observations. Perhaps the chemistry of this pack does need to be at a certain temperature to perform well, more so than other types of HV batteries.
I know others have said that it shouldn’t, but I can’t think of another explanation. Also, MG seem to have added battery warming technology to the cars with this pack chemistry.

TBH, the car has enough range for me, even with this peculiar behaviour, managing 3 or 4 days between charges even with this electron guzzling.
Spring will be the season the truth will come out I guess, looking forward to some 5 + miles kWh runs, Hyundai Kona go home

 

[Macadoodle]

It must be the heater but I can't believe it can be that bad.

I think I read that the heater can pull 7 kw, which is a chunk if true, prob half of what the traction motor is consuming at a reasonable speed ?
Plugged in on granny the other night, the app said pre- heat was pulling about 1.5 kw of the 1.7 kw the car was reporting to be receiving, car was toasty within the 10 mins allowed so 7 kw seems excessive for anything but a short blast

 

[Buster72]

I agree, and I think it's great that people are asking and that information is given in all the replies.
One question I would ask is is it too complicated, a change to the norm and do people worry to much about some elements of it.
The estimated range is just that and hence why referred to as a GoM, it's impacted by many of the factors people have stated already.
My previous, ICE, car had quite variable range mainly depending on how heavy my foot was on the loud and stop pedals. This for sure varied by over 20%, or more on the few track days I did.

When it gots close to zero I would go and fill up.Whats really good, as I have a home charger is that it it's lower.than I need.i.can just plug it in and don't have to search for a petrol station with a reasonable price .

Exactly that.
EV Range is really no different to conventional engine fuel consumption.
Nobody really believes the figures quoted for those. So why should they have complete faith in the figures quoted for an EV.
When I test drove an MG4 on Tuesday, the dealer was quoting the SE range as 218 miles because that is what MG quote.

Obviously there is a cold weather issue with the way the battery works and EV manufacturers should be made to make this transparent.

 

[MoDolph]

Exactly that.
EV Range is really no different to conventional engine fuel consumption.
Nobody really believes the figures quoted for those. So why should they have complete faith in the figures quoted for an EV.
When I test drove an MG4 on Tuesday, the dealer was quoting the SE range as 218 miles because that is what MG quote.

Obviously there is a cold weather issue with the way the battery works and EV manufacturers should be made to make this transparent.

Yes, and the heating needs to be part of the wltp test. Currently there is no benefit to the manufacturer for improving it as I believe that it is not even on for the test. The difference between the mg4 and our former leaf when it comes to heating energy use is huge even though their wltp efficiency is similar.

 

[Buster72]

Yes, and the heating needs to be part of the wltp test. Currently there is no benefit to the manufacturer for improving it as I believe that it is not even on for the test. The difference between the mg4 and our former leaf when it comes to heating energy use is huge even though their wltp efficiency is similar.

That is interesting. Any thoughts as to why. Maybe the MG4 heater is just more powerful and hence uses more energy?

 

[MoDolph]

That is interesting. Any thoughts as to why. Maybe the MG4 heater is just more powerful and hence uses more energy?

I'm guessing mainly the heat pump. It could also be insulation or how evenly the heat is delivered. Ive noticed that in the mg4 my upper body is often hot but my feet cold despite only having it set to window and feet. The leaf would always keep my feet toasty and this might have meant I could run at a lower temperature overall.

 

[Buster72]

I'm guessing mainly the heat pump. It could also be insulation or how evenly the heat is delivered. Ive noticed that in the mg4 my upper body is often hot but my feet cold despite only having it set to window and feet. The leaf would always keep my feet toasty and this might have meant I could run at a lower temperature overall.

Didn't realise it had a heat pump. What version do you have?

 

[MoDolph]

Didn't realise it had a heat pump. What version do you have?

The leaf had a heat pump, not the mg4. Once up to temperature it could maintain it using <500w. I wouldn't be surprised to learn that the mg4 was using 1kW+

 

[Buster72]

The leaf had a heat pump, not the mg4. Once up to temperature it could maintain it using <500w. I wouldn't be surprised to learn that the mg4 was using 1kW+

Understood. Thank you.

 

[Macadoodle]

I'm guessing mainly the heat pump. It could also be insulation or how evenly the heat is delivered. Ive noticed that in the mg4 my upper body is often hot but my feet cold despite only having it set to window and feet. The leaf would always keep my feet toasty and this might have meant I could run at a lower temperature overall.

As a leaf owner I totally agree. Leaf heating feels totally normal and evenly distributed, the 4 feels weird. Cold spots and misting of windows no matter what, feels like a half developed car in so many areas unfortunately

 

[remarkable1967]

Hi all
I’ll just chip in my wife’s Mg4 SR is very disappointing on range much worse than my 5 ever was I sure of that, at the moment when we collected the ar October 15 th I think it was , 100% charged Gom showed 229 miles available in normal mode not seen it go past 200 since when I have recharged it to 100% and allowed it to do a full balance session.

But having now driven an EV for a while I think I know most of the tricks to get the best range out of them, even my son who has been an EV driver for several years now, was saying yesterday the range in his Tesla model X is terrible at the moment, down around 80 or so miles at lease from summer figures so can only assume from that it as got to be the temperatures.

My MG5 was the same 40-60 miles down in winter temps I suppose the MG4 Trophy model might be a bit better than the SE LR in winter, the reason I say that is my 5 had the heated seats that I often used to keep warm rather than having the HVAC running for long periods as they run from the 12 volt battery, still needed HVAC on for shorts bursts to clear the windows but the seat heaters where great and the trophy as them, I know MG range figures are lower for the Trophy by about 10 miles but in cold weather it could maybe do better than the SE if you don’t have to run the HAVC as much which can batter the range.

I think we’ll know thinks will be better come spring also this is the wrong time of year to be getting a new car and expecting to to do the manufactures figures I think, as them figures will have been obtained in the very best of conditions and temperatures you can be assured of that.
Les.

Please excuse my stupidity on battery charging. I had previously said it was all like alchemy to me. I notice you mention that your car is a SR yet you talk of a "full balance session". I thought the whole cell balancing thingy was just on the LR as it has a different chemistry to the SR. When I previously asked advice on this, I'm sure I was told that the SR battery was the LFP type cell where you can happily just charge to 100% whenever and the LR battery was the NMC type cell that you shouldn't regularly charge up to 100% an also had to do the whole cell balancing thing periodically. I'm confused again.....

 

[Ayoull]

Please excuse my stupidity on battery charging. I had previously said it was all like alchemy to me. I notice you mention that your car is a SR yet you talk of a "full balance session". I thought the whole cell balancing thingy was just on the LR as it has a different chemistry to the SR. When I previously asked advice on this, I'm sure I was told that the SR battery was the LFP type cell where you can happily just charge to 100% whenever and the LR battery was the NMC type cell that you shouldn't regularly charge up to 100% an also had to do the whole cell balancing thing periodically. I'm confused again.....

All batteries require balancing due to the fact they're made up of individual cells connected together, due to how they're connected the same cells are constantly the first to be topped up and discharged in a battery, so balancing makes sure that the voltage across all cells is equalised to prevent voltage strain within the pack.

As increased discrepancy in voltages across cells can cause strain to the lower charged cells and cause failure over a period of time.

LFP batteries should be 100% charged and balanced atleast once a week due to how they hold their voltage and how the BMS has to try and keep track of the state of charge (SOC). LFP is also able to be charged to 100% without degrading the battery and has a 100% depth of discharge (DOD) rating, meaning you can take it to 0% without degrading the battery.

Where as NMC and NCA should he kept between 20 - 80% as much as possible with once a month balancing the cells just to keep the BMS tracking accurately. Voltage stress only happens at the 100% end of a cells charge range which is why LFP should be balanced and not just taken to 100%, occasionally not balancing won't hurt.

With NCA and NMC the reason for the 20-80% charge range is due to these batteries only having an 80% DOD range before you begin degrading the cells of the battery due to how the chemistry works in the battery.

NMC and NCA batteries are usually rated for around 500-1000 complete charge cycles, LFP are rated for usually 4000-10000 complete charge cycles depending on the manufacturer

 

[Jomarkh]

All battery types need the BMS to balance the battery once 100% has been reached.
If you do a lot of rapid charges to 80-90% it may take longer to balance.