MG ZS EV Limit charging by % on home charger

[gide]

Hello All
We have a new EV and have been charging at home most of the time. We can limit charging by the time limit on the app, which is the cheap rate between 9pm-7am. On a couple of occasions the charging got to high for our liking. Is there an additional way to limit the charge to a max percentage, say 80% for most of the time, except when we would go on longer trips.
TiA.

 

[Jomarkh]

Hi, does your model have a timer in the car you can set at 80%?
I just add 3.5 hours overnight and that covers my commute. During the summer I will change it to 2.5 hours.

 

[daverobbo]

Hello All
We have a new EV and have been charging at home most of the time. We can limit charging by the time limit on the app, which is the cheap rate between 9pm-7am. On a couple of occasions the charging got to high for our liking. Is there an additional way to limit the charge to a max percentage, say 80% for most of the time, except when we would go on longer trips.
TiA.

Long range or standard range ZS?

 

[gide]

Thanks @Jomarkh
Where would I find such timer?

 

[gide]

Long range or standard range ZS?

Thanks, It is the 320km range type.

 

[Bodgerx]

Thanks, It is the 320km range type.

SR…so answer is no.

MG’s daft restriction so that it encourages you to go to 100% more often so the GOM is more accurate on the LFP battery.

 

[gide]

SR…so answer is no.

MG’s daft restriction so that it encourages you to go to 100% more often so the GOM is more accurate on the LFP battery.

So it means we have to manage the charging more closely? Thinking about 80-85% max unless in front of a longer

 

[Susanna]

@gide
No harm will come to the battery if charged to 100%, but if you don’t want it to, then the only suggestion I have is to set the charging timer on the iSMART app. Let the charge in the car drop down to, for example, 40%, and then charge it for say 2 hours. Note down how much the 2 hours adds to the battery, and then you will get an idea of your individual charging capacity, and can tailor it to your requirements.

 

[gide]

@gide
No harm will come to the battery if charged to 100%, but if you don’t want it to, then the only suggestion I have is to set the charging timer on the iSMART app. Let the charge in the car drop down to, for example, 40%, and then charge it for say 2 hours. Note down how much the 2 hours adds to the battery, and then you will get an idea of your individual charging capacity, and can tailor it to your requirements.

Thanks @Susanna
I will do that and see how I get on.

 

[Lovemyev]

It would appear that you have the standard range model that is fitted with the LFP type chemistry battery.
It is recommended that you charge to 100% every single time you need to charge.
This is why MG has NOT offered standard range owners the ability to reduce the level of SOC via the App or in the head unit of the car.
You will notice, if you try and reduce the SOC level in the App back from 100% down to say 80% it will not hold at 80%.
It just keeps springing back up to 100% level, that is why.
Only the Long Range version offers the ability for the owner to set their preferred SOC level.
Different battery chemistry is the reason.
So, yes you could limit your SOC level down to 80% by stopping the charge at a given time, but remember the LFP battery is not designed to work this way and it could cause the battery to become out of balance.
Balancing only commences when the HV battery has reached 100% fully charged no THEN it starts the balancing process.
Oh …… Roughly one hour on a 7 Kw A/C wall box will add roughly 25 miles of additional range to pack, if you intend to limit the SOC level.
But I would advise caution here.

 

[Bodgerx]

It is recommended that you charge to 100% every single time you need to charge.

It isn’t.

 

[Lovemyev]

Standard range ZS EV model ( GEN 2 ) model with the LFP battery fitted it is, as you have NO control over the SOC level with this type of battery chemistry.
But NOT the long range ZS EV ( Gen 2 ).

 

[Bodgerx]

Standard range ZS EV model ( GEN 2 ) model with the LFP battery fitted it is, as you have NO control over the SOC level with this type of battery chemistry.
But NOT the long range ZS EV ( Gen 2 ).

Yes.

But no where do MG say it is always recommended to charge to 100% every time you charge. Which is what you stated.

In fact, the manual says only once a month for the full equalisation charge.

Going to 100% all the time has exactly the same effect on the battery health as the cobalt battery.

It just helps the GOM be more accurate the more times you hit 100% on the LFP, that’s pretty much it.

 

[jusher]

Hello All
We have a new EV and have been charging at home most of the time. We can limit charging by the time limit on the app, which is the cheap rate between 9pm-7am. On a couple of occasions the charging got to high for our liking. Is there an additional way to limit the charge to a max percentage, say 80% for most of the time, except when we would go on longer trips.
TiA.

The SE has to be charged to 100%, the Long Range can be set to charge to 80%. In fact the LR is recommended to be charged to 80%.

 

[Lovemyev]

The SE has to be charged to 100%, the Long Range can be set to charge to 80%. In fact the LR is recommended to be charged to 80%.

Thank you enough said !.
That is my total understanding also.

 

[Anf800]

Sorry, I’m confused here. Are you saying that it should be charged to 100% every time? I can’t find anywhere that says that in the manual. I realise I can’t set it to charge to less, say 80%, but why can’t I just charge it for a couple of hours then stop?

 

[Susanna]

Sorry, I’m confused here. Are you saying that it should be charged to 100% every time? I can’t find anywhere that says that in the manual. I realise I can’t set it to charge to less, say 80%, but why can’t I just charge it for a couple of hours then stop?

I too am confused! There is a world of difference between ‘can be’ and ‘must be’ charged to 100% every time you plug it in.

I have my own EVSE and tend to plug in for my 4 hour cheap rate once or twice a week, depending on my plans. I have read loads of stuff on the LFP battery chemistry requirements, and the only thing that is categorically stated, is that the BMS struggles with the GOM on the LFP battery when not fully charged. Taking this into account, you learn as you drive with the SR MG and go by your miles per kWh.

For anyone reliant on public charging, I assume a necessity to charge to 100% every time you plug in, might be more problematic.

Unfortunately, I haven’t been able to find any technical advice directly from MG on this subject, and it would be advantageous to all SR model owners to have a definitive statement from them. There is certainly nothing in the manual.

 

[jusher]

Sorry, I’m confused here. Are you saying that it should be charged to 100% every time? I can’t find anywhere that says that in the manual. I realise I can’t set it to charge to less, say 80%, but why can’t I just charge it for a couple of hours then stop?

You do not need to charge SE to 100% every time but unlike the LR you cannot set charge level.

 

[Jomarkh]

Do what you are comfortable with the battery has a 7 year warranty.

 

[Lovemyev]

You do not need to charge SE to 100% every time but unlike the LR you cannot set charge level.

That is 100% correct .
Of course owners of the standard range CAN stop the charge at any point manually if they wish.
But as @jusher has correctly said, you can’t set the charge level percentage like you can on the long range version.
So, unless you manually stop the charge, it will want to 100% SOC every time.
As LFP batteries are happiest when charged to 100% they are also conducting a balance cycle after the battery has reached 100%.
LFP batteries suffer less from battery degradation when consistently charged to 100% and are therefore more suitable for models with a shorter range, as these are likely to be charged closer to 100% and are lighter and cheaper to produce.
The fear here is I guess, if standard range owners continue to charge to 70 - 80% manually, then the battery never gets to perform the balance cycle and the battery / range could suffer as the cells become unbalanced.
Not providing the ability to set the SOC level below 100% in the standard range is the clue here.
The long range is almost the opposite in a strange way, because charging to 100% SOC is entirely possible and expected for longer trips, but charging to 80% SOC for daily use is the more recommended usage pattern.
This is why MG give you the option to set the charge level on the LR unlike the standard range model.
I know a lot of standard range owners were disappointed when they discovered they could not set the SOC levels from the App etc.
Until they discovered the reason that this had been done, was best suited to the LFP chemistry type of their cars.