Let’s see who gets rattled - charging details

lee graham

Well-known member
To be honest I’m kind of upset about this now. Not so much for me because I know the real range and what to expect, but more because it could leave missus stranded. She could see range as 218 and think that’s plenty for a 200 mile trip. When in fact the GOM is off by 50 miles. I will be contacting MG about it and see if it can be re calibrated.

I think I’ve figured it out, that by some mistake or wrong setting our GOM believes it has a 50kWh battery. If this was the case it would explain extra mysterious range and why it's constantly wrong.
 

lee graham

Well-known member
@Mark Holmes Of course i will update when I know.

Off topic, You know the best thing about eZS? Because it’s so cheap to run it makes it easier to visit friends and family. You can see how many miles we’ve done and its not cost a penny! Going to take twins to seaside today and again it will be free to get there.

By the way that ignore feature is great!
 

tintin

New member
Dear all,
In the openness of debate please see my charging photo below, charged to 96% with 24 minutes remaining on a 7 kWh charge and predicted range of 198 miles on normal mode....
What are your thoughts and does anyone else get this or is it just me. I will also post a fully charged photo once completed.
Fully charged or 99% charged display show 206 miles in normal mode, see photo.
Regards
I drive mostly around town, less than 30 MPH, but my consuption is 3.3 miles/kw with fully charged range of 161 eco, 151 normal, not had the mod done yet and my dealer says nothing wrong with the car
 

Mike

New member
I drive mostly around town, less than 30 MPH, but my consuption is 3.3 miles/kw with fully charged range of 161 eco, 151 normal, not had the mod done yet and my dealer says nothing wrong with the car
That sounds right to me. My GOM range is 146 in Normal with HVAC on at this time of year. My average speed is quite low with a mixture of motorway A roads lots of slow narrow country roads and town work, lots of short trips.
However, I’m getting well over 4 miles/kWh. Light acceleration, driving on the flat, good anticipation-early using the brakes, looking as far ahead as possible, plus all the usual advanced driving techniques. Obviously weather makes a big difference. Winter can make around 25% decrease in range.
 

Mark Holmes

Active member
I drive mostly around town, less than 30 MPH, but my consuption is 3.3 miles/kw with fully charged range of 161 eco, 151 normal, not had the mod done yet and my dealer says nothing wrong with the car
Again it all depends on driving styles, fast acceleration with heavy braking (not saying that is you) will make a huge difference, but also short trips will not allow your GOM to show the true picture as on each journey it will start low and then increase over the driving period.
 

KasEV

Active member
I do wish that my MG could easily and quickly be persuaded to display its SOC. I know that my overall miles per Kw is 4.2 and can be affected by my driving, etc, so if necessary I could easily calculate on my old slide rule the expected range to within about 20 miles.
I rarely charge to 100% so I have never seen some of the high mileages that others appear to obtain on their GOM. It's not that important to me!
I do enjoy driving my MG and hope that my contribution is useful.
PS. So far I have not had any updates done.
@Sriv
Your slide rule method will work most of the time for England if you roughly do the same journey daily but not for colder climates such as Canada / Norway in Winter or if your daily journeys are completely random.
As for SOC it has it own problems
Before the current GOM format many manufacturers used SOC. The complaints were absolutely ballistic. Especially in the winter. People kept complaining for example 100% - 20% charge gave me 100miles yesterday but only 80miles the day before and today 105 miles as the winter temperatures flactuated. Also people could not understand why 100% - 80% gave 20miles but 80%-60% gave only 15miles on the same day. After much thought and research manufacturers opted for our current real time predictive GOM. These adjust their predictions to your current driving conditions and indicate distance likely to be covered with the battery charge remaining by using "the most recent driving conditions data" to answer the question that EV users we indicating they wanted to know in the research several manufacturers conducted. Interestingly the question was not how much charge remains but rather how far could I travel.
The question GOM was therefore set to answer in real time with continuous self update is if driving conditions remain the same as they have been in the last few miles or minutes, how far will one travel.
So one will think problem solved. Well not it seems...... a new breed of problematic EV owners have arisen who believe they know better than the whole EV industry. They refuse to accept what the GOM is designed to do and keep complaining that GOM is not accurate based on their own private interpretations and calculations.
I guess is is the way of the world these days. The research on real time GOMs continues and some research groups are trying to device a method to link sat nav data into GOM so you can in advance get a predictive range remaining at various charging stations along you travel route at the start of your journey. Early days yet but the work in this area is underway.
Anyway drive safely and keep Covid safe.
 
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Kithmo

Active member
On my first full charge my GOM showed 163 miles fully charged, no HVAC and in normal mode, the average m/kWh was 3.9. Every full charge since, it has shown 162 miles (the average has gone up to 4.0 m/kWh).
It seems to be sticking to the WLTP figure for the car.
I'm finding that according to the odometer, I am consistently doing more miles than the GOM is losing as I drive so I am happy to rely on the GOM as being a good indicator as to the actual miles left and more. (y)
 

KasEV

Active member
I drive mostly around town, less than 30 MPH, but my consuption is 3.3 miles/kw with fully charged range of 161 eco, 151 normal, not had the mod done yet and my dealer says nothing wrong with the car
@tintin
Your dealer is absolutely right nothing wrong.
According to MG's information you data is within the range of what one should expect.
The efficiency of 3.3 is a bit on the lower side but that should improve once you start incorporating all the EV efficiency driving methods into your driving style.
And please do not worrying you head calculating why your GOM is not showing a fixed range of 140-144miles given you efficiency is 3.3.
The GOM is not designed to do that. The estimates it gives are based on current driving conditions and will vary daily and with the weather. The range gets lower if the winter is very cold.
 
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KasEV

Active member
On my first full charge my GOM showed 163 miles fully charged, no HVAC and in normal mode, the average m/kWh was 3.9. Every full charge since, it has shown 162 miles (the average has gone up to 4.0 m/kWh).
It seems to be sticking to the WLTP figure for the car.
I'm finding that according to the odometer, I am consistently doing more miles than the GOM is losing as I drive so I am happy to rely on the GOM as being a good indicator as to the actual miles left and more. (y)
@Kithmo
I absolutely agree. The current modern GOMs are relatively accurate. But be warned come the winter your range readings will drop if the weather becomes very cold.
Rotherham is not very cold so I guess there may be only a slight change.
My readings on 100% were 160miles in Jan- Feb.
Now they are 175-180miles.
Apparently best range is seen in autumn and spring and if one wants to maintain good range readings during summer then one should always park the EV in shade during the summer. I do not know how true that is but that is what I have heard and what I try to do.
 

lee graham

Well-known member
@Kithmo that sounds spot on. 4mkWh is easily obtainable and matches the WLTP figures.

My GOM is working!!! But only because I am averaging 4.7 which is what mine expects. I started with 215 mile range and I’ve done almost 70 miles and there is still 140 range still estimated.

0D11B85E-4481-4F62-9842-7B8CD45CCB38.jpeg
 

lee graham

Well-known member
Update: I managed 145 miles before needing another charge, when I connected I had 16% battery left. Please note that I’m happy with this range as it is what I expected, especially with motorway driving. But it goes to show how broken my GOM is.

68E24D9D-D7BE-4AE0-892A-88230DC8275E.jpeg
 

KasEV

Active member
Update: I managed 145 miles before needing another charge, when I connected I had 16% battery left. Please note that I’m happy with this range as it is what I expected, especially with motorway driving. But it goes to show how broken my GOM is.

View attachment 541
Hi Folks,
Still this myth of GOMs with fixed rigid 4.7 efficiency assumption lives on. Sad really...
Let's use the above data from @lee graham to bust this myth that the GOM works by assuming a fixed efficiency of 4.7
1. The current journey data shows efficiency of 4.7 at one point in the journey but later shows efficiency of 3.8
If the efficiency was fixed it will show 4.7 throughout. The data shows how the how system is self-updating and efficiency value in current journey is summative for the current journey up to the point in the journey where the reading was taken. As you can see at second point in journey the current data clearly shows 3.8 and is not fixed at 4.7 kWh per hour. If one were to go by the ridiculous rigid calculations that some have been using then at 3.8kWh the GOM should have been showing 161 miles at the start of journey.
2. Let's do more ridiculous maths....
If the GOM works on a simple addition, subtraction, multiplication, division bases like some want us to believe and the battery @16% is showing 39miles remaining, then at 100% it should have shown 244. Note at the start we are told it showed 215miles.
3. Also 145 to point of charge plus 39 remaining equals 184. This is not the 215 reading at the beginning.
Clearly the workings of the odometer is not based on simple multiplication and division or addition and subtraction maths.
One can continue doing further addition, subtraction, multiplication and division and things will never add up. Does that mean the odometer including the GOM is broken? Of course not.
Simple addition and subtraction basic maths will never work because rate of discharge of a battery is not linear and temperature and all the driving conditions that affect the GOM calculations vary considerably and also tend to be non linear.
Well....
The true situation is that we have 3 data sets in the odometer
1. Accumulative data..
This is the summative efficiency data from time of last reset of odometer to time reading is taken. This data tells one solely of the past and is self updating.
2. Current Journey data..
This data is summative from start of current journey to the point where reading was taken. It tells you about the current journey so far and is self updating.
3. The GOM... Distance on remaining charge.
This is the forward predictive section of the odometer. It tells you how far one may travel with the remaining charge in the battery if the driving conditions in which the car has been driven for the last X miles and/or Y minutes remains the same. It is self updating and not fixed on a rigid efficiency value.
The GOM is dynamic and its value is dependent solely on data from the most recent travel.
For example if you drove 40miles or 60 mins yesterday, then you charge your car overnight and switch it on in the morning, the odometer uses data from only the last X out of the 40 miles / last Y minutes out of the 60mins of yesterday's journeys and the immediate battery SOC to give you its first GOM reading. It then immediately starts to self update with today's driving conditions and today's battery state of charge as you drive along. It then continuously self updates mile by mile or minute by minute in keeping with your most recent X miles or Y mins of driving.
Because almost every factor that affects the GOM value in mathematical terms is exponential and there is complexity of correlations between the various factors, simple addition, subtraction, multiplication and division will not work if one tries to work out a GOM value by themselves.
Unfortunately as you can see there are people who deem themselves more knowledgeable than the whole of the EV industry and the makers of the odometer technology and such people will try with their basic maths to make all sort of conclusions. All such conclusions will be wrong.
So please do not get confused by those who continue to claim their GOMs work on a rigid fixed basic multiplication formula with a fixed efficiency of 4.7
GOMs are not designed to work that way.
Some also think the GOM is designed to give a minimum achievable distance no matter what. Unfortunately that is also not true.
 

Mark Holmes

Active member
Okay here it is with photo’s
Left this morning with GOM showing range of 216 after being fully charged.
Temp 12 degrees, Tyre P Front 36 and rear 38 driving when on motorway between 60 and 65 Mph. Not fans, heating or cooling used.

Outward trip left with 216 on GOM.
Drove 11 miles 200 shown on GOM, at 24 miles 184 shown on GOM, arrived after 43 miles 162 shown on GOM (Difference of 16 miles to what I had actually travelled). Average 4.1 KWh per mile.

Return trip left with 161 miles on GOM
Drove 11 miles 145 shown on GOM, at 27 miles 127 shown on GOM, arrived after 44 miles 113 shown on the GOM (Difference of 4 miles to what I had actually travelled). Average 4.6 KWh per mile.

Total difference travelled 87 miles, total variance compared to what was shown 16 miles, which if my maths are correct is a difference of 13.92%
If that remains true 216 - 13.92% means a prediction range of 185.93 miles
My anticipated range should in 187 miles based on my average is 4.4 miles per kWh.
Not sure if the photos updated are in order.

I don’t think that bad at all I’ll do a long run when I can..
 

Attachments

KasEV

Active member
Okay here it is with photo’s
Left this morning with GOM showing range of 216 after being fully charged.
Temp 12 degrees, Tyre P Front 36 and rear 38 driving when on motorway between 60 and 65 Mph. Not fans, heating or cooling used.

Outward trip left with 216 on GOM.
Drove 11 miles 200 shown on GOM, at 24 miles 184 shown on GOM, arrived after 43 miles 162 shown on GOM (Difference of 16 miles to what I had actually travelled). Average 4.1 KWh per mile.

Return trip left with 161 miles on GOM
Drove 11 miles 145 shown on GOM, at 27 miles 127 shown on GOM, arrived after 44 miles 113 shown on the GOM (Difference of 4 miles to what I had actually travelled). Average 4.6 KWh per mile.

Total difference travelled 87 miles, total variance compared to what was shown 16 miles, which if my maths are correct is a difference of 13.92%
If that remains true 216 - 13.92% means a prediction range of 185.93 miles
My anticipated range should in 187 miles based on my average is 4.4 miles per kWh.
Not sure if the photos updated are in order.

I don’t think that bad at all I’ll do a long run when I can..
The whole issue is that the GOM is not base on your so called average. That is the issue.
One can do multiplication and division all day long using any average you may choose and it will not work.
The GOM is based on values derived from the last Xmiles of your most recent journey and is self updating. This means changes minute to minute.
Exactly were each EV manufacturer sets their "X" usually remains undisclosed.
Using an average derived from values at the end of a journey or several journeys will never work unless one knows the manufacturers value of X and can drive to exactly that number of miles then take a GOM reading. But even then you may deviate because of temperature and all the other factors that influence the GOM calculation. We can take a few factors and go into detail but for simplicity sake let's look at ambient temperature of 12 degrees is only part of the temperature equation. The other part is battery temperature. This does not depend on ambient temperature alone. It depends on how hard the battery has been working, whether it has just been recently charged etc. So where is your temperature chart that allows you to adjust your calculations for battery temperature variation?
Unfortunately it is absolutely clear from the basic maths your are trying to use and your insistence that your GOM is base on your so called average that you have absolutely no clue what you are talking about.
The GOM is based on data from the last Xmiles of your most recent journeys.
Since one does not knows the exact value of X and the maths involved in computing the GOM is complex, simple addition, subtraction, division and multiplication can not be used to calculate the GOM readings.[/QUOTE]
 
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lee graham

Well-known member
Very interesting @Mark Holmes thanks for the photos and data.

I believe that will Not stay true though, my GOM was accurate for the first 70 miles as I traveled at an average of 4.7. It was the return journey that it really messed up.

if you look at my first photo I have 141miles remaining, but after 76 miles that estimate is out window and I have range anxiety trying to find charger. That is where problem lies.

I’ve emailed mg.

Btw your first photos, your GOM is off by 11 miles after only 43 miles. It expected you to be averaging 5 mkWh to match its estimated range.

Imagine trying to discuss a faulty speedometer and some Donkey was trying to tell you how a speedometer works.

edit: changed monkey to donkey.
 
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GordieG

Member
@KasEV
For the avoidance of doubt, I don’t disagree with a lot of your sermonising on GOMs. What I do disagree with (and I apologise for repeating myself - something you rarely do) is the manner in which you talk down to people and hammer your points home again and again and AGAIN. You are forever coming on like a little league Albert Einstein and insist on writing a thesis every time you take to the forum.
 

KasEV

Active member
@GordieG,
My sincerest apologies to you and all the members for any offence caused. The issue of misinformation / disinformation about range and GOM and the owner distress and difficulty to salesmen caused is one that I seen first hand and one which prompts me to write on comments that are not based on the scientific basis of GOM.
All said and done we all here to learn so apologies if my comments are not in the appropriate tone.
 

KasEV

Active member
@KasEV
For the avoidance of doubt, I don’t disagree with a lot of your sermonising on GOMs. What I do disagree with (and I apologise for repeating myself - something you rarely do) is the manner in which you talk down to people and hammer your points home again and again and AGAIN. You are forever coming on like a little league Albert Einstein and insist on writing a thesis every time you take to the forum.
@GordieG,
Please let me apologise in advance should anything I write cause you any offence.
I note your awareness of the empirical workings of GOM and your wish that one does not sermonize their contribution. I just want to ask if you also have an opinion on use of racist language and insults
Imagine trying to discuss a faulty speedometer and some monkey was trying to tell you how a speedometer works.
One would have thought sermonizing scientific facts may cause offence but more so insults and racist language bungled with non scientific baseless assumptions.
Well.... what do you think?
 

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