Battery capacity not match with consumption figures

[dam92]

Hi All.

Trophy LR 24plate owner here.

Can you please help me to understand the following figures. It doesnt add up to the spec.
I bought this car with 8k miles second hand.
I believe Trophy LR has a 64kWh battery?.
So lets say usable capacity is at least 60kWh.
After driving some time, i have reached the 50% capacity.
But, car says i have only used 24kWh since last charge. My last charge was 100%.
So, if 24kWh is 50%, total capacity is 48kWh .
I am using this for short journies, less than 3-4 mile per day. So miles per kWh is 3.8, which is fair.
But why it's showing 50% for just 24kWh usage?

Edit;:- please note that i dont have a problem with estimated range figures, which can jump up and down significantly based on driving pattern. Estimations/ predictions vary all the time.

But distance travelled since last charge and consumption since last charge are real time calculations (not estimations) based on raw data, which are unique to that specific time period ( time since last charge).

 

[OriginalBigAl]

You can drive yourself crazy doing all the mathematical permutations involved in getting an "accurate" or even sensible answer . The two figures above and under the power graph are more illuminating and along with the regen figure and the photos you have provided it can be done to jiggle the figures that makes sense. Also if you have just got the car some of those averaged out numbers will be from a previous owner . Just doing one balance charge to reset the system most likely won't be enough ,you will need to put your miles on the car and again a balance charge to reset and calibrate it to your style of driving. Sadly , just taking a snapshot view of a couple of numbers does not make a sensible result . After two years of ownership I think I'm starting to understand the maths , then it sends out some curve ball numbers to again confuse the issue. Most have given up trying to understand the algorithms and are happy to drive on just the m/kwh figure. Also the usage is not perfectly linear from 100% down to lower limits so that will confuse the issue when trying to calculate what should be , on the face of it , simple into as you have discovered , not!
If you find a formula that consistently works you would gain instant hero worship status on this forum.

 

[dam92]

You can drive yourself crazy doing all the mathematical permutations involved in getting an "accurate" or even sensible answer . The two figures above and under the power graph are more illuminating and along with the regen figure and the photos you have provided it can be done to jiggle the figures that makes sense. Also if you have just got the car some of those averaged out numbers will be from a previous owner . Just doing one balance charge to reset the system most likely won't be enough ,you will need to put your miles on the car and again a balance charge to reset and calibrate it to your style of driving. Sadly , just taking a snapshot view of a couple of numbers does not make a sensible result . After two years of ownership I think I'm starting to understand the maths , then it sends out some curve ball numbers to again confuse the issue. Most have given up trying to understand the algorithms and are happy to drive on just the m/kwh figure. Also the usage is not perfectly linear from 100% down to lower limits so that will confuse the issue when trying to calculate what should be , on the face of it , simple into as you have discovered , not!
If you find a formula that consistently works you would gain instant hero worship status on this forum.

Thank you for your reply.
First of all, all previous owner data has been reset, and I’ve personally reset all three range meters.

If you divide the total miles driven by the energy consumption figure shown on the driver display, you get approximately 24 kWh. This matches the figure displayed in the infotainment system as well. So you can see regen figure doesn't make sense.

This isn't just a matter of one or two figures—multiple data points consistently point to a usable battery capacity of around 50 kWh. That just happens to be the standard capacity of the SE (Standard Range) model.

So, either the Trophy’s battery is significantly degraded, or the original higher-capacity battery has been replaced with a 50 kWh unit at some point.

Interestingly, the OBD reading still shows a State of Health (SOH) of 98.4%, which would be considered normal for a one-year-old car. This makes the situation even more confusing.

I will do a charge from about 10% to 100% on a fast charger to get an independent reading about the capacity.
Considering the losses associated with the fast charging, I should get a capacity reading that matches the 98.4% capacity.

 

[OriginalBigAl]

Just to confuse things a bit further , I have mine reporting in km and kWh. Today mine says 14.5 kWh/100km or just under 7km/kWh. Under the graph bit it says total consumption 21 kWh/100km, and above current usage 24 kwh. So there is a discrepancy 7km or under 5km/kWh. Taking into account the regen and adding it to the consumption figure within reason finds the total consumption figure , but taking into account one is for km done, the other for kWh/100 km.
I recently charged to 80%, it gave an estimate of 340 km ( optimistic ) I have just done 150 km on 40% ( 25kWh ish ) or 6km/kWh; the range I have left is 123 km? 40% * total consumption figure as a guess not taking into account any future regen. The trouble is all these are constantly variable figures or variable averages so trying to get them to compute to a figure you want or expect is not easy. To make things comfortable I work off a real full 100% range of 380 km; anything extra is a bonus. ( summer of course ) and trying to work out the battery capacity is frustrating.
I leave that to the EVSE saying how many kWh it's put in, and working out the maths from there accounting for a bit of wastage.

 

[Bam Bam]

So, either the Trophy’s battery is significantly degraded, or the original higher-capacity battery has been replaced with a 50 kWh unit at some point.

Wow - an LFP Trophy would be pretty unusual in the UK!

Would have advantages (should do more cycles), but I can see it might feel like a downgrade.

Seems very unlikely, though, as I think the LFP battery pack might be a different size. Not much space in the boot under the carpet.

 

[EvTek23]

@OriginalBigAl is absolutely correct in what he says about the readings you have presented. It's not just simple maths using battery capacity, energy used, time and distance.
The LR has a usable battery capacity of 61.7kWh, the remainder is masked because of the NMC battery chemistry and the way the cells loose capacity due to use and charging, this also brings about the 80% charging health mode, and 100% long range mode. The SR using LFP batteries has none of the above with just regular charging to 100%. But that's a whole different topic covered on other threads.
Back to your question @dam92, I don't think resetting the 3 range meters and owner data will change what the GOM (Guess-o-meter) calculates what the remaining range is likely to be, its built up over months monitoring driving style and conditions, charging habits, temperature at the very least. More time and miles are required to build up a more accurate picture in your ownership. Unless you know the previous owner you have no idea of their driving style, driving conditions, charging habits etc.
What does stand out from your 2 pictures are:
The amount of regen. I've never seen figures that high in my experience. So either a lot of stop start motoring or steep inclines you are going down.
The average speed is very low, so again this points to stop start driving.
The accumulated time of 14 hours for a distance of around 100 miles.
I think you've got to be patient and build up your own data to get a more accurate picture before all the stats start to make sense.
If this your first EV you can still basque in the glory of efficiency, and around the equivalent of 150 MPG.

 

[dam92]

@OriginalBigAl is absolutely correct in what he says about the readings you have presented. It's not just simple maths using battery capacity, energy used, time and distance.
The LR has a usable battery capacity of 61.7kWh, the remainder is masked because of the NMC battery chemistry and the way the cells loose capacity due to use and charging, this also brings about the 80% charging health mode, and 100% long range mode. The SR using LFP batteries has none of the above with just regular charging to 100%. But that's a whole different topic covered on other threads.
Back to your question @dam92, I don't think resetting the 3 range meters and owner data will change what the GOM (Guess-o-meter) calculates what the remaining range is likely to be, its built up over months monitoring driving style and conditions, charging habits, temperature at the very least. More time and miles are required to build up a more accurate picture in your ownership. Unless you know the previous owner you have no idea of their driving style, driving conditions, charging habits etc.
What does stand out from your 2 pictures are:
The amount of regen. I've never seen figures that high in my experience. So either a lot of stop start motoring or steep inclines you are going down.
The average speed is very low, so again this points to stop start driving.
The accumulated time of 14 hours for a distance of around 100 miles.
I think you've got to be patient and build up your own data to get a more accurate picture before all the stats start to make sense.
If this your first EV you can still basque in the glory of efficiency, and around the equivalent of 150 MPG.

Thanks for the reply.

Yes, its very steep hills within 2 miles, so it just regen for 2 miles and use about 40% motor power uphil. Hence that unusual regen figure.

You are correct. Estimations, predictions vary all the time. I dont have a problem with distance predictions. I know those can vary significantly. I usually dont pay attention to the distance figure much. I only care about the battery % and efficiency since last charge, which based on most recent data.


My argument is based on the calculations (not predictions) done using raw data available so far.

1st raw data is distance travelled from last charge. This doesnt depend on the previous driver or any driving patterns. Its just pure distance.

2nd raw data is efficiency.
How many miles done per kWh since last charge. Last charge is the key here. This also doesnt depend on the previous owner.

3rd is the battery %. You would expect this cannot be far off from the designed capacity after 1 year, unless something is wrong.

So distance travelled (so far) , 94 miles.
Efficiency(so far) , 3.9 miles/kWh.
This gives roughly 24kWh.
Used capacity( so far) 50%.

 

[dam92]

Just to confuse things a bit further , I have mine reporting in km and kWh. Today mine says 14.5 kWh/100km or just under 7km/kWh. Under the graph bit it says total consumption 21 kWh/100km, and above current usage 24 kwh. So there is a discrepancy 7km or under 5km/kWh. Taking into account the regen and adding it to the consumption figure within reason finds the total consumption figure , but taking into account one is for km done, the other for kWh/100 km.
I recently charged to 80%, it gave an estimate of 340 km ( optimistic ) I have just done 150 km on 40% ( 25kWh ish ) or 6km/kWh; the range I have left is 123 km? 40% * total consumption figure as a guess not taking into account any future regen. The trouble is all these are constantly variable figures or variable averages so trying to get them to compute to a figure you want or expect is not easy. To make things comfortable I work off a real full 100% range of 380 km; anything extra is a bonus. ( summer of course ) and trying to work out the battery capacity is frustrating.
I leave that to the EVSE saying how many kWh it's put in, and working out the maths from there accounting for a bit of wastage.

Yes.This is confusing. But your figures of 25kWh for 40% at least come closer to the designed capacity of 62kWh isnt it?.
I dont have a problem with estimated range. I know that can vary a lot depend on number of conditions.
But, distance travelled from last charge, and power consumption from last charge are actual figures. Not prediction.

Guess only way to confirm this to do a full charge. I will update this after a full charge.

 

[dam92]

Wow - an LFP Trophy would be pretty unusual in the UK!

Would have advantages (should do more cycles), but I can see it might feel like a downgrade.

Seems very unlikely, though, as I think the LFP battery pack might be a different size. Not much space in the boot under the carpet.

Yes. I am most likely wrong here. I was just trying to make sense the calculated figures.

 

[tsedge]

My LR Trophy definitely has the full 61kWh useable, I can see what goes in from my home charger and allowing for losses it takes what it should do. e.g. last night I went from 50%-100% and it put 33.5kWh in, which is about 30kWh into the car.

 

[dam92]

My LR Trophy definitely has the full 61kWh useable, I can see what goes in from my home charger and allowing for losses it takes what it should do. e.g. last night I went from 50%-100% and it put 33.5kWh in, which is about 30kWh into the car.

Thanks. So a charge should confirm my doubts.

 

[decrep]

Could your discrepancy be caused by an unbalanced battery?

 

[dam92]

Could your discrepancy be caused by an unbalanced battery?

Possible. But 10kWh? Im sure that much unbalance should trigger battery protection systems.

 

[Martinonline]

I do not understand how the car works out how much energy it uses and where. My discharge display shows the car has used 8kWh driving, no regen, no other usage, from the last charge (not 100% but 60% and balanced). There is confusion in that the graphical display for the last 50 miles states my average usage was 6 miles/kWh whereas the driver's display for 36.3 miles since charge shows 4.0 miles/kWh.
The infotainment screen currently shows 44% and 120 miles remaining.

So from the discharge screen my 8kWh usage consumed 16% of the battery. Scaling up that gives a 100% figure of 50kWh. That is wrong based upon my last 5% to 100% charge in July which my Ohme EVSE said consumed 62.85kWh. I do not believe that the car 'loses' over 10kWh whilst fast charging.

In summary something is amiss in the car's calculations.

(As an aside, do you have intelligent battery heating switched on?)

 

[dam92]

I do not understand how the car works out how much energy it uses and where. My discharge display shows the car has used 8kWh driving, no regen, no other usage, from the last charge (not 100% but 60% and balanced). There is confusion in that the graphical display for the last 50 miles states my average usage was 6 miles/kWh whereas the driver's display for 36.3 miles since charge shows 4.0 miles/kWh.
The infotainment screen currently shows 44% and 120 miles remaining.

So from the discharge screen my 8kWh usage consumed 16% of the battery. Scaling up that gives a 100% figure of 50kWh. That is wrong based upon my last 5% to 100% charge in July which my Ohme EVSE said consumed 62.85kWh. I do not believe that the car 'loses' over 10kWh whilst fast charging.

In summary something is amiss in the car's calculations.

(As an aside, do you have intelligent battery heating switched on?

Thank you.
This gives me some closure.
The 6 miles/kWh figure in entertainment graph is the same for me. Looks like that isn't updating and it shows some junk value. So figures in the car are somewhat wrong.

 

[EvTek23]

@dam92, by way of example my latest charging and consumption figures. The journeys were mixed motoring on A roads, motorways, with some hills as I live in bucks.
The battery was at 79% after the previous charge, and I used it for 88.7 miles, the battery was then at 46%. I charged it back up to 80% (with balancing) so an indicated 33% battery usage. My charger indicated 22.88kWh total input power for the charge period. This is roughly 1/3 of the battery capacity if you factor in charging losses of around 10%. for AC charging.
I've included 2 pictures, 1 of the energy pie chart and the second the energy consumption graph.
I still find your regen figure abnormally high, and wonder if this is skewing your figures depending on how the BMS uses the regen figure. Could it be possible that it's actually including the regen as use, rather than a benefit. With much lower regen figures this would hardly be noticeable, but with a regen of 58% the figures don't add up.

 

[dam92]

@dam92, by way of example my latest charging and consumption figures. The journeys were mixed motoring on A roads, motorways, with some hills as I live in bucks.
The battery was at 79% after the previous charge, and I used it for 88.7 miles, the battery was then at 46%. I charged it back up to 80% (with balancing) so an indicated 33% battery usage. My charger indicated 22.88kWh total input power for the charge period. This is roughly 1/3 of the battery capacity if you factor in charging losses of around 10%. for AC charging.
I've included 2 pictures, 1 of the energy pie chart and the second the energy consumption graph.
I still find your regen figure abnormally high, and wonder if this is skewing your figures depending on how the BMS uses the regen figure. Could it be possible that it's actually including the regen as use, rather than a benefit. With much lower regen figures this would hardly be noticeable, but with a regen of 58% the figures don't add up.View attachment 38609View attachment 38610

Thank you for the detailed explanation.

Please correct me if im wrong.
According to these details, you are saying , even though pie chart shows 17kWh, charger put 22kWh into the battery?.

so, roughly, 17kwh for 33%. That means 1/3 of battery, so 100% means 51kwh.

This is exactly what I'm getting too.
So this is not only me.

Even though charger put 22kWh, in we can only use 17kWh. This is about 22% loss.
So we can say 10% loss when charging and another 10% loss when discharging.

This means we lose about 10kWh from total capacity?

Either that or MG's calculations are super wrong.

High regen figure is because of the daily 2 mile downhill drive.

The 6mi/kWh graph is wrong. I have seen several graphs from others and so far all of them show 6mi/kWh, which is impossible.

MG needs to get their calculations correct.
Seems like only thing reliable in these cars are the four wheels that spin when you press the accelerator and stopping when you press brake.

 

[EvTek23]

Yes those are the figures displayed for the 88.7mls the drivers display was showing 5.0mls/kWh, which ties in with 17 kWh the pie chart is showing (88.7 ÷ 5 = 17.6).
The driver's display for the battery use and mls/kWh maybe stand up to closer scrutiny with the charging process, which is saying 33% battery use for 88.7mls and for this charge 5.0 mls/kWh.
This would make the range of an LR with nominal 64kWh capacity of 266mls.

 

[dam92]

Yes those are the figures displayed for the 88.7mls the drivers display was showing 5.0mls/kwh, which ties in with 17 kwh the pie chart is showing (88.7 ÷ 5 = 17.6)
The drivers display for the battery use and mls/kwh maybe stand up to closer scrutiny with the charging process, which is saying 33% battery use for 88.7mls and for this charge 5.0 mls/kwh.
This would make the range of a LR nominal 64kWh capacity of 266mls.
View attachment 38612

So You put 22.8kWh ito the car for 88.7 miles.
If you take out 10% for charger loss (which is huge by the way) it's 20.5kWh. That means efficiency is actually 88.7mi/ 20.5kWh=4.3miles/kWh. Not 5.

What is even worse is that regen doesn't seem to be doing any good. According to MG's own calculation, they don't take the regen benefit into account. This can be seen in a case like mine, which has huge amount of regen due to the hilly areas.
99% won't notice this or won't care.

MG's calculations are super wrong for some reason.

 

[Tight Git]

So You put 22.8kwh ito the car for 88.7 miles.
If you take out 10% for charger loss (which is huge by the way) its 20.5kwh. That means efficiency is actually 88.7m/ 20.5kwh=4.3miles/kwh. Not 5.

What even worse is regen doesnt seem to be doing any good. According to MGs own calculation, they don't take the regen benefit into account. This can be seen in a case like mine, which has huge amount of regen due to the hilly areas.
99% won't notice this or won't care.

MGs calculations are super wrong for some reason.

According to my SR last month it was doing 4.4 miles/kWh but my Zappi tells me that from the amount used to charge the car and the mileage I did it was doing 3.7 miles/kWh.