Battery capacity not match with consumption figures

[gary333]

Empty the car to close to zero and fill it up to 100%. Pointless looking at the software as it's shite. You then have your answer what the loss is.

 

[dam92]

I just don't understand what you mean.

I thought the issue was the car isn't accurately reporting where the power is going.

Now you are claiming that this has something to do with the battery capacity.

Or are you claiming that the car is misrepresenting the efficiency of the motor?

I don't think you are being consistent with your complaint here, but are trying to make out that something is outrageous.

If you want to get more accurate figures on the uses get an OBD device and measure it all accurately.

Im sorry for the confusion.

If you see the 1st message, you can see i was telling about used power and efficiency figures doesn't match the advertised battery capacity. That's the primary problem.


Then if you carefully follow the conversation, you can see few other also reporting similar figures. Calculated capacity is about 51kwh, which is similar to my case.

But the chargers seems to be putting fairly acceptable amount of energy in to the car (about 61-62kwh).
People also provided their own charging data.

Then came new questions, where did that 10kwh go?.
Does it have to do with poor efficiency of the charger?. Poor efficiency of the inverter?.
What is the actual output we get?.

 

[dam92]

Empty the car to close to zero and fill it up to 100%. Pointless looking at the software as it's shite. You then have your answer what the loss is.

Yes. Thats what im planning to do.
I will update this once its done..

 

[Martinonline]

I believe, @dam92, that you are right to question the information you have been given based on the data the car provides.

However, it would be interesting for you to state, exactly, what concerns you have and what the implications are for you.

For example, I bought my Trophy for its range and upgraded specifications, eg rear view camera etc. I did not know about NMC and LFP batteries nor charging/discharging efficiency.

If the range had been substantially lower than I was told then I would have been mightily put-out. But it is not. The car takes ~67kWh for a 100% balanced charge and that meets what I was told the battery size was. It would be nice to have a higher charging efficiency but that probably, but not certainly, with a more expensive car.

Back to your figures: if you assume that the miles/kWh value is correct and the mileage is correct then the usage data is correct. However, by doubling the value you assume the usage is linear over the 100%, which may not be true. Certainly the GOM does not believe that because it shows a remaining mileage of 124 miles for the last 50%.

The 'WhatCar Range and Efficiency Test' video (winter) with a Trophy ER came to the conclusion that the usage efficiency was accurate over their 100% usage test.

If that is correct for your 50% usage then a 50kWh battery would give you 195 miles, a 60kWh 234 miles with the (assumed linear) GOM 248 miles.

You can test these figures by running down your battery and then let us know the results and then follow with a metered charge to check the efficiency.

Good luck.

 

[dam92]

I believe, @dam92, that you are right to question the information you have been given based on the data the car provides.

However, it would be interesting for you to state, exactly, what concerns you have and what the implications are for you.

For example, I bought my Trophy for its range and upgraded specifications, eg rear view camera etc. I did not know about NMC and LFP batteries nor charging/discharging efficiency.

If the range had been substantially lower than I was told then I would have been mightily put-out. But it is not. The car takes ~67kWh for a 100% balanced charge and that meets what I was told the battery size was. It would be nice to have a higher charging efficiency but that probably, but not certainly, with a more expensive car.

Back to your figures: if you assume that the miles/kWh value is correct and the mileage is correct then the usage data is correct. However, by doubling the value you assume the usage is linear over the 100%, which may not be true. Certainly the GOM does not believe that because it shows a remaining mileage of 124 miles for the last 50%.

The 'WhatCar Range and Efficiency Test' video (winter) with a Trophy ER came to the conclusion that the usage efficiency was accurate over their 100% usage test.

If that is correct for your 50% usage then a 50kWh battery would give you 195 miles, a 60kWh 234 miles with the (assumed linear) GOM 248 miles.

You can test these figures by running down your battery and then let us know the results and then follow with a metered charge to check the efficiency.

Good luck.

Thank you. I'm not complaining about the estimated range — I understand that estimates can vary.

My concern is with the usable capacity of the battery. Based on my own observations and data from others, it appears to be around 51 kWh, including auxiliary loads. That suggests around 10 kWh of capacity is effectively lost or unavailable, which is a significant discrepancy.

As a power electronics engineer, I design power converters and chargers for a living, so I tend to be especially sensitive to these kinds of figures.

These values are typically calculated using current and voltage sensor readings. If the reported usable capacity is this far off, it suggests there may be an issue — either in measurement accuracy, calibration, or system design.

It's not about cost. In fact, I’ve seen far better accuracy and efficiency from even low-cost Chinese power converters.

 

[Martinonline]

Thank you for your explanation and as you say there may be an issue with measurement factors et al.

And MG may not have the best designed system but unless you look at all EVs you cannot say this is not typical of the market at this price point.

Will you be running down your battery to sub 5% to see if the usage figure exceeds 50kWh? And to see how many miles you covered? (For the miles/kWh figure.)

Finally, have you checked to see if the (not so) intelligent battery heating is on?

 

[dam92]

Thank you for your explanation and as you say there may be an issue with measurement factors et al.

And MG may not have the best designed system but unless you look at all EVs you cannot say this is not typical of the market at this price point.

Will you be running down your battery to sub 5% to see if the usage figure exceeds 50kWh? And to see how many miles you covered? (For the miles/kWh figure.)

Finally, have you checked to see if the (not so) intelligent battery heating is on?

Yes. That's the plan. At least wait until it goes below 10%. I need to do an equalise charge as well to get it to the optimal capacity.
No battery heating enabled.
Yes I agree. Its not the best and I wouldn't expect it to be at this price tag. Let's see what happens.
From my experience on designing these type of converters, I know it's not too much to ask for reasonably accurate calculations. On the other hand, it's much much more complex to design the power electronics and its controller firmware. MG seems to have designed the motor controller well. No sudden jerks and it's pretty smooth.

That's why I am surprised to see this discrepancy in the figures.

 

[Coulomb]

That's why I am surprised to see this discrepancy in the figures

The firmware in the motor controller must be written by different engineers than the display firmware. Possibly a different section within SAIC, or possibly by a different company altogether.