MG4 Range

[fnegroni]

I believe the LFP battery pack is more energy dense between 50-100% than it is between 0-50%, so it's not a true linear depletion of energy. Thus 100% SoC range showing more than double the 50% SoC range is not unusual.

The BMS tracks voltage.
On a cold day voltage will be lower, especially past 50%. Therefore the ambient temperature and the battery pack temperature does have an impact. You would expect the BMS to compensate for it when reporting the SoC but there might also be trend weighted factors that get reset when charged to 100%
In my experience the percentage variation above and below 50 % had been fairly minimal and way over ridden by the consumption trend over the recent trips.

 

[Rolfe]

But the LPF battery has a very flat discharge curve, so the voltage changes very little until the battery is getting close to empty.

 

[Derek25]

Following on from my previous monthly posts, here's my efficiency for October. This was anything but a routine month as I've been in the south of France for the whole of October. So, roughly 2,000 of those miles were motorway and temperatures were warmer than the UK. The two factors probably cancel each other out. Average monthly efficiency so far has been May 3.8; June 3.9; July 3.6; August 3.7; September 3.7; October 3.5.

My latest monthly efficiency for those following it. Average monthly efficiency so far has been May 3.8; June 3.9; July 3.6; August 3.7; September 3.7; October 3.5. November 3.1. Good to be still averaging more than 3 and getting close to 190 miles.

 

[tsedge]

That's very good - with a 30% winter drop you could easily be looking at 2.6mi/kWh based on your summer average.

 

[Derek25]

That's very good - with a 30% winter drop you could easily be looking at 2.6m/kWh based on your summer average.

It's been a fairly mild November so that's helped. I expect it to be lower in December-January, but first impressions in the really cold weather of the last few days are that efficiency is holding up reasonably well.

My latest monthly efficiency for those following it. Average monthly efficiency so far has been May 3.8; June 3.9; July 3.6; August 3.7; September 3.7; October 3.5. November 3.1. Good to be still averaging more than 3 and getting close to 190 miles.

Here's my average for December. Still getting 3.1 miles/kWh average. The mild weather probably has a lot to do with that as does one rather slow 100-mile journey in Christmas traffic. Average monthly efficiency so far has been May 3.8; June 3.9; July 3.6; August 3.7; September 3.7; October 3.5. November 3.1; December 3.1.

 

[tsedge]

That's very good. I am down at around 2.6mi/kWh at the moment.

 

[AB71]

I’ll post mine when I go out before I make the final decision

There was a guy on Twitter yesterday who lives in a cold climate says he and his friends agree the colder the weather the better the car performance ???

 

[Ian Key]

There was a guy on Twitter yesterday who lives in a cold climate says he and his friends agree the colder the weather the better the car performance ???

If it was an ICE car that could be true as cold air is denser than warm air so the car will be getting more oxygen into the cylinders.

 

[AB71]

If it was an ICE car that could be true as cold air is denser than warm air so the car will be getting more oxygen into the cylinders.

Honest to god it was an orange trophy!
Will I find it and post it for you?

If it was an ICE car that could be true as cold air is denser than warm air so the car will be getting more oxygen into the cylinders.

Ian

 

[siteguru]

That doesn't say the efficiency improves, just that they "work". (Which is true - the heater/AC isn't subject to the engine running, so it is easy to warm them up - remotely - and get into a nice warm car and start driving; not something you can usually do in an ICE car). ICE cars can get sluggish due to "thick" oils etc. So whilst O2 intake may improve, everything else deteriorates so the net impact is worsened MPG.

 

[tsedge]

@siteguru has it. EVs are much easier to live with in the extreme cold, even if their range is heavily reduced. Many ICE cars just don't function at all unless they are kept in a warmed garage or a block heater or similar is used.

 

[JonnyG]

Maybe they also have a heat pump in Swedish models which would help at -30°C.

 

[Coulomb]

Maybe they also have a heat pump in Swedish models which would help at -30°C.

Except that heat pumps have a hard time working at very low temperatures, since they have to remove heat from the environment. It may well be that the Swedes get resistive (e.g. NTC or PTC) heaters.

 

[tsedge]

My understanding is that EU versions get a heatpump except for Ireland, which I think is derived from UK spec - but I could be wrong.

Heatpumps can work at very low temperatures but it is all about the design of the installation - for example Teslas are very clever at generating waste heat in the motors and scavenging it to boost the effectiveness of the heatpump.

Generally, however, a PTC heater is best at providing maximum instant heat, at the cost of efficiency. (NTC heaters are not used for safety reasons).

 

[MSvirus]

Heat pumps work the best in milder temperatures. It is where they really shine. If a good design of installation is done, it can be better at low temperatures, but the advantages is smaller. For example my norwegian indoor heat pump, which is a good nordic model (here SCOP is calculated for the lowest level of possible surround temperatures), which has small discrepancy between COP and SCOP, meaning it is well designed for low temps. At high outside temperature it will provide over 5 kW of heating for every 1 kW of effect transmitted to it (COP is then >5). At low temperatures (like -20 degrees C) it probably will provide around 2 kW of heating for every 1 kW added power, and at -30 it probably will be nearer to 1kW/1kW. So it decrease with temperature, but still will be better than the energy usage of the PTC element at most temperatures, but at -40 degree C it might be under 1 actually. Not many use their electric car then anyway.

 

[MSvirus]

That doesn't say the efficiency improves, just that they "work". (Which is true - the heater/AC isn't subject to the engine running, so it is easy to warm them up - remotely - and get into a nice warm car and start driving; not something you can usually do in an ICE car). ICE cars can get sluggish due to "thick" oils etc. So whilst O2 intake may improve, everything else deteriorates so the net impact is worsened MPG.

The oil which is used in the drivetrain of the MG4 also get a lot thicker with the cold, and will cause more drag than in the warm weather. The MG4 oil do have a very low pour point at -60 degrees C, and with 28 centiStokes kinematic viscosity at 40 degrees C and 6,0 cSt at 100 degrees C, it is a fairly thin drivetrain oil. It is a API group 3+ GTL derived oil (popularly called synthetic in all countries except Germany, where it would be called semi-synthetic), and I would guess the oil can lubricate near the -40 degrees C mark, but then again it would have the kinematic viscosity of several thousand cSt. I guess the cooling temp sensors in the MGs will reduce power when the drivetrain gets too hot, but 6,0 cSt at 100 degrees is on the thin side if using it on track. Both EVs and ICE cars will have metal components that when it's cold they will have clearances way outside of their tolerance window, which also causes drag (and wear), but the problem is bigger with ICE cars as they have a lot more of both oils and metal components.

 

[Robf]

Don't forget the overall increase in force that is required to push the car through denser colder air....; every little helps

 

[halogen]

me and bunch of friends Bricked our MG4 SR exceeding the brochure range of 425km to 445km not bad for a 51 kWh battery...fun times.

 

[MSvirus]

Consumption on my Xpower with a bit wide winter tyres (235), in heavy snow and -6 degrees C was 20 kWh/100 km (~3,1 miles/kWh), after it was fully heated, over a 100 km drive on norwegian backroads, with an average of around 70 km/h. That will give about 300 km of range in this condition.

 

[siteguru]

Bricked? Are you using that term in its usual way? (Caused the device to fail in a major way making it very difficult if not impossible to recover).