Guess-o-meter calculations. What is your true range and how much you should trust the car's Algo.

[Ian Key]

I read someone talking about a test (on YouTube I think but I haven't seen it) where they deliberately let some EVs go right down to nothing and they said there was about ten miles of crawling along in tortoise mode between showing zero range and actually coming to a standstill.

I'd be interested in watching that video if anyone knows where to find it.

You mean this one?

 

[Ian Key]

I am in agreement here as I am seeing 270 miles of range after a full charge on my MG5 ev. I don’t want to rely on that but I have to admit it is a bit confusing, especial when I leave my house and have covered maybe 500 yards and I have used 4 miles of power. As I will be making my first long journey to Cornwall in mid July I would appreciate any comments from seasoned ev drivers with MG5 or similar

You might be better posting your question on the MG5 forum

 

[Rolfe]

You mean this one?

Thank you so much! Today's exercise video!

 

[stouens]

Ok people, get those calculators out.

We know the guess-o-meter calculates your range using some dark-art-algorithm from your previous-recent driving style. That is not what I would like us to calculate. I have an SR car and when full it shows a range from 236 to 254 which clearly is wrong ( but makes me feel good..... it is good to fool yourself sometime).

Anyway, your quest ( should you wish to accept it) is to use some calculations and compare with the results from FROM LAST CHARGE data. So lets say you charge to 100%. Then drive merrily till you get to 20% battery left. Please do the following calculation.

SR has 50.8 KWh usable battery , so
(50.8 * (1-(20/100)) = 40.64 KWh used
see how many miles you have gone on the From Last Charge screen. Let us assume X
then X/40.64 will be your miles/KWh

Compare this with what is shown in your From Last Charge screen. I bet they will not be the same. Mine had 11% difference.

Now, hopefully the actual miles you have driven From Last Charge is correct (or we are in big trouble) Also 50.8 usable should be quite accurate since our car are newish (note 1 or 2% degradation is nothing, so let's ignore that). So the only dodgy figure is the % of battery left.

So this is the calculation I hope you will do and post some results. This is for fun and don't get worked up about it. If you drive around 4.1 m/KWh on average you should do 210 miles easy (210/50.8=4.1 m/KWh). In town that is easy until we get to winter again. If you do motorway driving I would say account for (3.7*50.8=187 miles) and you cannot go wrong.

You don't have to charge to 100% of course. If you charge to 80% and drive to 20% then the equation becomes 50.8* (1-((80-20)/100))=30.48 kwh used
If you have a long range version use 61.7 instead of 50.8......Simples


I believe the reason for all discrepancies is that with LFP batteries because the voltage across the cells does not drop much from fully charged to discharged, cars are finding it difficult to guess how much battery you have left. This is why MG and TESLA et all say charge your car to 100% regularly, so the system can reset itself.

Of course the long range version uses NCM so the Cells's voltage drops as it discharges and hence the car knows more exactly how much battery you have left. So if you good sires do this example I think your discrepancies should be less than us with LFP batteries.

This is just for fun so whatever the answer, relax and enjoy this wonderful car. So far nothing can touch this car for fun and value.

My real fun is that we have solar panels which in this sunny weather create about 3-3.8 KW often exceeding 30 KWH per day. I charge from my 3 pin plug in the garage, effectively I am running cost free. I

 

[fshuk1]

I am in agreement here as I am seeing 270 miles of range after a full charge on my MG5 ev. I don’t want to rely on that but I have to admit it is a bit confusing, especial when I leave my house and have covered maybe 500 yards and I have used 4 miles of power. As I will be making my first long journey to Cornwall in mid July I would appreciate any comments from seasoned ev drivers with MG5 or similar

Just to help you out I would suggest the following
Find out what is the USABLE size of your battery. If you are travelling long distance on motorways and want to not have range anxiety, Battery percentage x Usable battery size x 3.7 = what range you can be comfortable with. Try to charge before this range ends.

And if you are in town/B road driving same calculations but use 4.0 ie Battery percentage x Usable battery size x 4 = what range you can be comfortable with. Try to charge before this range ends.


I hope this helps until you get to know your car better