@MG expert Charging 80% useful?

[TaxiMan]

come on guys, did you do this stupid sh*t with your petrol or diesel cars. What a lot of faffing around worrying about your battery. Just charge it every day if you have a home charger, (that is what it is for), its just a car, keep the tank full because its easy to do with a home charger and if there is ANY problem with the battery just pass it on to MG to fix.

I did not buy an EV to have to worry about the battery, as it is there is many other things that can go wrong but as it has a 7yr warranty I don't even worry about it one little bit. However in saying that my nearest MG Garage is 89 miles away so it is a pain in the backside to get them to look at anything. My heater blower has just started acting up in that when you try to go above 3 bars it just cuts out and initially I thought it was a fuse but no, when you turn the HVAC off and then back on it works perfectly until you try to above 3 bars again, so it is NOT a fuse but some other (probably software) problem. It is due its first service in Nov so I have asked them to look at the heater problem then.

Unless you are keeping the car long term past the warranty I would not even consider in any shape or form maintain some made up charging regime which is NOT even proven to be any benefit, all the inconvenience is just baffling to me, its a car and you probably will change it in 4 years, just enjoy it for what it is.

Regards

Frank

SPOT ON! Some folk take it to another level!

 

[KasEV]

OK Folks, let's be practical about this.
Real life for me is that battery range and charging can be a big bother.
I think @Frank is right. One has to just plug in and make sure the battery is topped up every night and just carry on with more important things.
And the 20% to 80% business........
One may just forget it. It is for the Purist only according to some analyst.
Their recommendation is......
Just drive to destination and plug in if you can. Otherwise make sure you have enough power to return home and plug in when you get home. Apparently this is how the EV manufacturers actually expect EV owners to behave and that is one of the assumptions used to conduct all their analysis and future projections.
The 20% to 80% issue comes into play on motorway long journeys etc but for EVs with less than 52kWh batteries manufacturers realise how cumbersome that can be and apparently do not give any emphasis to it in their analysis. Apparently if one factors 20% to 80% charging into the equation the EVs with less than 52kWh become absolutely undesirable to the average man on the street.
For example for the ZS EV, it will mean saying to the owners their vehicles will have to be charged strictly every 70 to 80 miles after initially charging to 80% at time of purchase. This is too rigid and apparently disfunctional and will put people off purchasing the EV.
Well that is what strict 20%-80% means for the ZS EV on the average.

 

[justme]

I usually keep my cars 10 years and I don't do loads of miles. My plan so far has been to put it on charge at home when there are 80 miles or less left and charge to 120-130 miles range unless I plan a long journey the next day when I will charge to full. I've seen nothing to change my mind.

 

[KasEV]

That's OK. It is a good regime.
It may not work for some people.
In the last month I often do 100-120 miles or more in a day for several days then do not drive for several more days.
So when I am busy, I have to charge at every opportunity rather than stick to a strict regime.
If things become normal post Covid I may go back to a better regime just for the sake of being "battery prudent".

 

[ARvanHAS]

@Johnberg51
Well whatever the case the problem with EVs is Batteries. 44.5kWh or 75kWh both are a problem.
This is why an EV has to be driven for over 25000miles before it beings to achieve emission equivalence with a comparable ICE.
Because of the initial emissions hit of EV manufacturing due mainly to Batteries one can only hope Batteries become better and more environmental friendly if not we will just be replacing carbon emissions with more complicated environmental, social and political issues related to manufacturing of batteries.

OH dear, I'm having a deja vu. ?

@Frank after a while you'll start to notice the voltage won't be what it used to be. But like you said, 500000km? Who cares about that?

 

[Johnberg51]

Thanks all, I have just decided I don't care enough about the battery life to worry about a charging regime, I will now just continue with my plug it in every night as I have done for the last 8 months I can't be bothered (as whotsername says) because one day when I need it the most I will have to travel off to Glasgow or Edinburgh when not expecting it so at least this way I am always fully charged "ready to go".

Frank

Watch this video at 12 minutes and see what can happen:

 

[KasEV]

Watch this video at 12 minutes and see what can happen:

Very excellent Video.
Yes constant top up without discharging is a problem but my understanding is that the BMS slow charging to suit the state of charge of the battery once it hits 80% and this helps prevent the battery decaying.
Not sure if the BMS on the 2010/2011 cars were that good.
Anyway it is sensible to significantly discharge the battery before recharge there is no doubt about that.
Just one thing to mention about swapping the current ZS EV batteries. This can easily be done but not for a larger capacity one. I have investigated that issue with a ZS EV insider and at present all that can be done is swap for the same battery. Something to do with weight balance, suspensions and weight carry capacity of the floor of the ZS EV. Apparently all these factors will be improved in the upcoming 2021 model and the batteries will go up to 52kWh.

 

[Johnberg51]

Very excellent Video.
Yes constant top up without discharging is a problem but my understanding is that the BMS slow charging to suit the state of charge of the battery once it hits 80% and this helps prevent the battery decaying.

I think slower charging starts at about 95%.
You can see it on my usage diagram.
I charged from 23:30 until 9:15 the next morning from 28 to 100% with a 16A granny. (Mostly I charge to 80%]
Every bar is 15 minutes and you can see that only the last two bars are shorter.
One bar is about 0,9 Kwh.

BTW the black bars is solar power

 

[KasEV]

I think slower charging starts at about 95%.
You can see it on my usage diagram.
I charged from 23:30 until 9:15 the next morning from 28 to 100% with a 16A granny. (Mostly I charge to 80%]
Every bar is 15 minutes and you can see that only the last two bars are shorter.
One bar is about 0,9 Kwh.

BTW the black bars is solar power
View attachment 518

Good diagram,
The BMS is clever than you think.
The lowering of power in most modern EV including starts from 80% battery capacity as standard.
What you diagram show is that your power setting was so low that the BMS decided it did not need to be lowered till is was at 95%. If you use a higher power setting to charge, the BMS will start lowering the power earlier and if you set your upload power too high the BMS will allow only the appropriate power to go through to the battery from 0% to 80% then at 80% it will start lowering. That is how it works.

 

[Johnberg51]

OK, so when you use a 7 Kw wallbox it is slowing down at 80%.
For me charging at 16A really is more than enough.

 

[KasEV]

OK, so when you use a 7 Kw wallbox it is slowing down at 80%.
For me charging at 16A really is more than enough.

Yes.
You are doing everything right but most people in England will find what you do difficult. Also you are an Engineer so you can work things out most people are not so we have to explain in simple terms.
So practically.....
What it means if one is not travelling far then use the car till it shows 30 miles minimum 25 miles then charge to 120 miles or 130 max. This would be ok for the battery in terms or the 20 - 80 charging.

 

[Johnberg51]

Is there anybody who can confirm that the voltage shown in “electrical information” is just the voltage on the plus and minus of the HV battery?
When 100% charged this is about 454V.
I know the battery is build with 108 serial elements of 110 Ah each.
The charging cut-off voltage of a Lion cel is 4,2V, that means you should not charge it to 4,3V or so because then you better run away
When you calculate 108 x 4,2 you get 454 V ? this is not a coincedence.
I only want to tell that my conclusion is that MG is charging to the max without any top protection buffer like p.e. Nissan who stops at 4,1 V pro cell.
OK, I trust the MG but maybe in China they wanna reach the limit with the less of battery.
This is what is making me so motivating to charge to 80%?
Sorry for my critical way of thinking, I could be wrong

 

[KasEV]

Is there anybody who can confirm that the voltage shown in “electrical information” is just the voltage on the plus and minus of the HV battery?
When 100% charged this is about 454V.
I know the battery is build with 108 serial elements of 110 Ah each.
The charging cut-off voltage of a Lion cel is 4,2V, that means you should not charge it to 4,3V or so because then you better run away
When you calculate 108 x 4,2 you get 454 V ? this is not a coincedence.
I only want to tell that my conclusion is that MG is charging to the max without any top protection buffer like p.e. Nissan who stops at 4,1 V pro cell.
OK, I trust the MG but maybe in China they wanna reach the limit with the less of battery.
This is what is making me so motivating to charge to 80%?
Sorry for my critical way of thinking, I could be wrong

Johnberg51
Do not worry too much.
The BMS works well but I guess MG may have to add new software that allows charging to stop at 80% for us to have confidence when charging. Maybe in the 2021 version.

 

[Johnberg51]

Look what I found on a Thai website:

ทำไมแบตเตอร์รี่ MG ZS EV ถึงเสื่อมยาก?

รถยนต์ไฟฟ้า

blink-drive.com

Our battery is 50 Kwh but the software is limiting the state of charge (SOC) to 90% and this is making our battery 44,5 Kwh usable.
I never read this before and even the MG website don’t talk about this, strange because this is giving the car more value!
If this is true I am really happy because this would increase the amount of charge cycli very much and maybe I can forget charging to 80%?

Google translated Thai to English

But if to let me guess about the battery price of the MG ZS EV, I would like to take an example of a chevy bolt battery to compare it. The chevy bolt has a battery of about 60 kWh or 288 cells. The Bolt is at $ 15,000 or 450,000 baht, while the MG ZS EV has a battery of 50 kWh, but can be used only 44.5 kWh because the software lock can not use more than 90% SoC (State of Charge), so I look. That the battery cost of MG is likely to be cheaper than 400,000 baht per pack (excluding tax for some countries) And if you think about it in a straightforward way, one module will drop approximately 25,000 baht (this is a fun calculation. From the world battery price Which is expected that in the future in the next 8 years, the battery price will be 1 times cheaper than before

 

[shikoku14]

That would contradict Tesla Bjorn's assertation that 42.5kWh is the maximum usable capacity of the battery. Given the testing he has done on nurmerous EVs and the explanation he gives about a minute into this video (from 12 mins in) as to why it is 42.5kWh, I'd believe his maths on this.

 

[Johnberg51]

It is really difficult to analize the real truth.
It could be that this 2 Kwh difference is for the bottom protection buffer.

 

[KasEV]

Look what I found on a Thai website:

ทำไมแบตเตอร์รี่ MG ZS EV ถึงเสื่อมยาก?

รถยนต์ไฟฟ้า

blink-drive.com

Our battery is 50 Kwh but the software is limiting the state of charge (SOC) to 90% and this is making our battery 44,5 Kwh usable.
I never read this before and even the MG website don’t talk about this, strange because this is giving the car more value!
If this is true I am really happy because this would increase the amount of charge cycli very much and maybe I can forget charging to 80%?

Google translated Thai to English

But if to let me guess about the battery price of the MG ZS EV, I would like to take an example of a chevy bolt battery to compare it. The chevy bolt has a battery of about 60 kWh or 288 cells. The Bolt is at $ 15,000 or 450,000 baht, while the MG ZS EV has a battery of 50 kWh, but can be used only 44.5 kWh because the software lock can not use more than 90% SoC (State of Charge), so I look. That the battery cost of MG is likely to be cheaper than 400,000 baht per pack (excluding tax for some countries) And if you think about it in a straightforward way, one module will drop approximately 25,000 baht (this is a fun calculation. From the world battery price Which is expected that in the future in the next 8 years, the battery price will be 1 times cheaper than before

Well now you do not have to worry too much. Also the manufacturers have been spending loads of money on studying charging behaviour and have noted that the average EV user is more like @Frank than yourself. So that has been factored in when designing the BMS to achieve best protection for each battery capacity.
I will not be surprised if this is true but I must say I have not seen it in any MG data specifications so one will have to check.

 

[Johnberg51]

Well now you do not have to worry too much. Also the manufacturers have been spending loads of money on studying charging behaviour and have noted that the average EV user is more like @Frank than yourself. So that has been factored in when designing the BMS to achieve best protection for each battery capacity.
I will not be surprised if this is true but I must say I have not seen it in any MG data specifications so one will have to check.

I really did not seen anything about this either in any specifications.
I really hope it is true, then we can all do the same as Frank.
This article is really making my day

 

[Johnberg51]

so one will have to check.

Just send an Email to MG Thailand in Bangkok.
I hope they can tell more.

 

[KasEV]

@Johnberg51,
Tried the translation software and read it in the English translation. To my surprise the author of the article seems to suggest the material in the article came from MG in England.
So I am a bit confused because I have not come across it before in any of the ZS EV English language manuals or advertising materials.
I am not sure if this 50kWh capacity is true. Please update with any information you receive from Thailand.