Best battery charging practices

[profdraper]

I wonder if longer term owners of the 2021 MG ZS EV might be able to share their experience about battery charging?

I've owned the ZS EV for about six months now and almost always charge at home on a 7kW wallbox scheduled for overnight off-peak power rates. This practice follows the MG recommended 20% to 80% charging rule & with a full charge & battery equalization every six weeks or so. It has niggled me however about waiting for that low 20% charge state of around 50km and then having to wait 4 hours to charge up again. A little like 'caught with my pants down' should an emergency arise.

Well that happened last night when I had to rush my wife to a hospital emergency department in the middle of the night, but before the charging scedule took place & with a low battery charge. A bit stressful to say the least. It all worked out fine & we did manage to get there and back, my wife is OK, however, I still really don't like this low battery period and subsequent long charge time.

Does anyone have any experience with longer term ownership and strictly following the charging recommendations (or not) as per above? Supposedly, if we don't, we risk 'memory effect' and more rapid battery degradiation over time. I'm thinking now to ignore this and to keep the battery topped up more & with more regular home charging but wondered about others' experiences here? Many thanks in advance.

 

[Jomarkh]

I don't let my 5 go to 20% before charging I just keep it between 50-80% incase I need to got somewhere quickly.
I have a four hour slot to charge my car cheaply so over night normally add 30-40% depending on the weather.

 

[drmcw]

Memory effect is nickel cadmium batteries not lithium. Just try and avoid a high state of charge for a prolonged period and going low. Why not just keep it at 80%?

 

[profdraper]

Thanks everyone. I have had quite a few replies form other UK & AU fora. Seems like nearly everyone charges regularly to 100%. Clarification?

If so, then how does this avoid the (much longer) battery balancing phase? Or, does everyone also battery balance regularly? Or simply cut off and interrupt that? Thanks again.

 

[drmcw]

100% charge is the only time battery balancing takes place so there is no avoidance. I have a leaf where you can't set a charge limit so it will usually get charged to 100% but then I use it every day so it doesn't stay at 100% for long. Still have all 12 bars after 5 years.
Get the car to fit your life not the other way around. If 80% is sufficient then use that, if not go higher.

 

[Gadget Geek]

20% to 80% are the optimal ends of a bell curve. A state of charge anywhere within that range is fine. I prefer to have enough range in my car for those unforseen emergencies and usually keep it between 60% - 80%, with 100% for a long journey the next day or cell balancing every few weeks.

Glad everything turned out OK for your wife.

 

[smoked]

i'd never let it drop down to 20%. i have two cars and even with that in mind i'd still keep this 50% and above. its just not worth that range anxiety by doing the drop and charge thing you are doing.

i max it 80% though unless i have a long trip.

 

[Lovemyev]

We owed a Gen1 ZS EV for over two years and covered almost 20,000 miles, before moving to a facelift LR model in March 22.
99.9% of our charging needs where done at home, from our 7.0 Kw wall box.
I would try, as much as possible to charge between 30% to 80% to be nice to my battery ?.
Only charging to 100% when taking on a longer trip.
Balancing the battery as per MG’s instructions.
On the original factory BMS software, the car would take about 45 mins to 1 hour to balance.
This increased after the BMS software was applied, it could take anything from 2 hours to 4 hours to balance.
Others have reported similar conditions.
I can say that after owning the car for two years, that they was definitely some battery degradation noticeable in the pack.
I would estimate that the SOH of the pack to be around 94%. Others have seen similar figures with this type of mileage and age.
On the SR facelift model, MG recommend that owners charge to 100% every time, due to the battery chemistry.
LR owners have been advised of a different strategy.
Charge up to 80% for many every day use, then charge to 100% for the longer trips only.
Heat is the batteries worst enemy.
Regular rapid charging will have a long term effect on the life of the HV battery.
Degradation is unavoidable long term, that it why it is worth factoring this into your choice of battery size in your EV, if you intend to keep the car for a longer term.

 

[Tank53]

Had my trophy for 3 weeks just using the granny charger at the moment, retired so don't need car in a hurry usually. Is this detrimental long term or beneficial, don't know whether to invest in a wall charger, any advice out there?

 

[dgs99]

I wonder if longer term owners of the 2021 MG ZS EV might be able to share their experience about battery charging?

I've owned the ZS EV for about six months now and almost always charge at home on a 7kW wallbox scheduled for overnight off-peak power rates. This practice follows the MG recommended 20% to 80% charging rule & with a full charge & battery equalization every six weeks or so. It has niggled me however about waiting for that low 20% charge state of around 50km and then having to wait 4 hours to charge up again. A little like 'caught with my pants down' should an emergency arise.

Well that happened last night when I had to rush my wife to a hospital emergency department in the middle of the night, but before the charging scedule took place & with a low battery charge. A bit stressful to say the least. It all worked out fine & we did manage to get there and back, my wife is OK, however, I still really don't like this low battery period and subsequent long charge time.

Does anyone have any experience with longer term ownership and strictly following the charging recommendations (or not) as per above? Supposedly, if we don't, we risk 'memory effect' and more rapid battery degradiation over time. I'm thinking now to ignore this and to keep the battery topped up more & with more regular home charging but wondered about others' experiences here? Many thanks in advance.

Don't worry about it. the Battery is guaranteed for 7 years anyway, I would have long traded in my MG5 by then.

 

[Lovemyev]

Had my trophy for 3 weeks just using the granny charger at the moment, retired so don't need car in a hurry usually. Is this detrimental long term or beneficial, don't know whether to invest in a wall charger, any advice out there?

Wall boxes will allow a much faster turn around time when charging.
I am retired also, but find a wall box a much better option to be honest.
Another thing to consider, is what energy tariff you are using.
If you are on a standard variable rate, then you can charge at any time of the day or night, and the cost will be the same.
If on the other hand, if you are on a dedicated EV lower rate “Off - Peak” tariff, then charging in the early hours of the morning is the way to go.
Many EV owners favour this type of tariff.
The usual time frame for off peak is about 5 hours with a lot of providers.
If you have a Granny lead, then this is difficult to gain the most from that cheaper rate, because it’s rate of charge is so slow.
With a wall box, to can expect to receive about 25 of range gained, for every hour you spend on charge.
So, five hours on a wall box, gives you about 125 of range in that cheap rate period.
That is important if you have an EV with a larger battery.
Speed vs cost I guess you could say ??.
I decided to have a wall box installed way back in 2015.
The Granny is purely a back up or taken when we spend a few days from home, when I know the charging infrastructure is going to be rubbish !.

 

[Gadget Geek]

My Kona is on the granny charger as I type, making use of the excess solar generation. I rarely use my 7kW Pod-Point charger.

 

[Thebiglad]

I've had my Gen 1 ZS EV since sept 2021 and 9500 kms.

I generally plug in before there are any messages on the dashboard, such as today when she is showing (ECO, Hvac off, ) 90-100 kms left. She'll get plugged in tonight early evening and left plugged in until maybe 9 am tomorrow morning by which time I'll at least 300 kms on the guessometer.

Never been asked to do any "battery balancing" she just works ...

 

[profdraper]

On the SR facelift model, MG recommend that owners charge to 100% every time, due to the battery chemistry.
LR owners have been advised of a different strategy.
Charge up to 80% for many every day use, then charge to 100% for the longer trips only.

Have read different opinions from owners on this (& even that MG still recommend 80% for the SR). Referring to home charging here, 7Kw or 11Kw.

Whichever: the LFP battery for the SR facelift vs. the NMC battery for the LR. This appears completely consistent for other EVs (with the exception of the Atto 3 LFP blade on both SR & LR models), eg, Tesla has LFP in the short range, NMC in the long range; ditto Volvo only has the NMC for its C40 & XC40.

It is charging recommendations that seem to differ. Those EVs with LFP batteries all reccommend charging to 100% on a regular basis, no problem.

For the MG, there appears to be very differing opions about this for the Short Range facelift LFP, both in the UK and in Australia. Some are adament that MG recommends 80% but cannot see to find this in any MG literature. As an LFP battery I fail to see how charging practices might differ from those of BYD or Tesla recommendations, but there may well be some other internal differences [?}

 

[Lovemyev]

Have read different opinions from owners on this (& even that MG still recommend 80% for the SR). Referring to home charging here, 7Kw or 11Kw.

Whichever: the LFP battery for the SR facelift vs. the NMC battery for the LR. This appears completely consistent for other EVs (with the exception of the Atto 3 LFP blade on both SR & LR models), eg, Tesla has LFP in the short range, NMC in the long range; ditto Volvo only has the NMC for its C40 & XC40.

It is charging recommendations that seem to differ. Those EVs with LFP batteries all reccommend charging to 100% on a regular basis, no problem.

For the MG, there appears to be very differing opions about this for the Short Range facelift LFP, both in the UK and in Australia. Some are adament that MG recommends 80% but cannot see to find this in any MG literature. As an LFP battery I fail to see how charging practices might differ from those of BYD or Tesla recommendations, but there may well be some other internal differences [?}

When MG released the ZS EV ( Gen 2 ) face lift model, owners of the standard range model, where surprised to find they they could NOT reduce the SOC level back from 100% either in the App, or n the head unit.
Pulling back the slider control from 100% back to say 80% resulted in the slider control springing back to 100% ???.
Not the case on the long range models though.
This caused a barrage of questions from new standard range owners.
MG responded by saying this feature had intentionally been removed on the standard model because it was fitted with the LFP battery chemistry type unit.
Therefore by doing this MG had already made the decision for standard range model owners for them.
Is it possible to charge a standard range model to a chosen SOC level ?.
Yes - I guess it still possible with a bit of effort from the owner, by timing a charge to finish before the battery hits 100% with a bit of simple “Man Maths” but this is not what MG intended owners of standard range cars to be doing really.
Had they wanted this to happen, they would have made the charging level percentage option available in the settings.
Long range models were still left with the ability to set the charging level percentage of course.
In fact, in the charging display screen it clearly shows that charging to 80% for the majority of your charging needs, then dragging the slider to 100% SOC for longer road trips, when the maximum level of charge is required.
Of course ANY of these choices on either model with different battery packs, can be made by the owners.
Like always these are recommendations, that will be strictly adhered too by some and ignored by others of course.
Personal choice !.

 

[Robf]

I charge my (MG EV LR) between 40% and 90%. I also have a 30kw leaf that always gets charged to 100% and is still showing 100% battery (no degrigation) after 6 years ?‍
I do find that 4 hrs (Octopus go) only usually takes the MG to just over 80% from 40% so it never really reaches the 90%.

 

[Kithmo]

It makes one wonder if it's worth getting the long range, seeing as for day to day use, 80% of the LR is 218 miles (WLTP) and 100% of the SR is 198 miles.
Is it worth the extra money for an extra 20 miles if you only do long journeys occasionally ?

 

[N2STY]

It makes one wonder if it's worth getting the long range, seeing as for day to day use, 80% of the LR is 218 miles (WLTP) and 100% of the SR is 198 miles.
Is it worth the extra money for an extra 20 miles if you only do long journeys occasionally ?

The long range is definitely worth a bit more money the 80% charge is good for the commute to work and every day stuff but then for them longer journeys that just charge to 100% and avoid them high DC charging costs works really well not to mention LFP definitely don't like the cold

 

[profdraper]

When MG released the ZS EV ( Gen 2 ) face lift model, owners of the standard range model, where surprised to find they they could NOT reduce the SOC level back from 100% either in the App, or n the head unit.
Pulling back the slider control from 100% back to say 80% resulted in the slider control springing back to 100% ???.
Not the case on the long range models though.
This caused a barrage of questions from new standard range owners.
MG responded by saying this feature had intentionally been removed on the standard model because it was fitted with the LFP battery chemistry type unit.
Therefore by doing this MG had already made the decision for standard range model owners for them.
Is it possible to charge a standard range model to a chosen SOC level ?.
Yes - I guess it still possible with a bit of effort from the owner, by timing a charge to finish before the battery hits 100% with a bit of simple “Man Maths” but this is not what MG intended owners of standard range cars to be doing really.
Had they wanted this to happen, they would have made the charging level percentage option available in the settings.
Long range models were still left with the ability to set the charging level percentage of course.
In fact, in the charging display screen it clearly shows that charging to 80% for the majority of your charging needs, then dragging the slider to 100% SOC for longer road trips, when the maximum level of charge is required.

well, that’s a new one on me: fixed slider on the charge level!?
I wonder if iSmart gets around this … the only other possibility then is to schedule for less than 100% how odd, have not seen this reported with any owners here in Australia.

 

[Lovemyev]

The long range is definitely worth a bit more money the 80% charge is good for the commute to work and every day stuff but then for them longer journeys that just charge to 100% and avoid them high DC charging costs works really well not to mention LFP definitely don't like the cold

Absolutely spot on !.
A lot will depend on your usage case of course.
I find that charging our LR to 80% SOC on a very regular basis from day 1 suits our travel needs just fine !.
We have now covered 11,000 miles since collection about 14 months ago.
Finding that charging to 100% had only been necessary about 5 - 6 times over that time.
Always charging from home on our five hour “Off Peak” tariff via EDF tariff.
I have the head unit in car set to ONLY charge in the preset allotted times and NOT to continue charging after the “Off Peak” rate has been achieved.
Our day rate tariff is WAY more expensive of course.
The car has only been charged twice on a CCS rapid charger and that was carrying out by the dealer.
Once before we collected the car and once when it went in for its first service.
I find the extra range buffer on the LR model works a bit like the reverse tank that the older petrol cars had many years ago ?.
Again it’s down to matching the size of your battery down to your user case.
If you match your pack size correctly to your usage case and add in some extra margin, then your reduced range in the winter or if you suffer from any battery degradation, then you have a car that is going to suit your needs for a good number of years to come.
Yes - Of course you can charge a smaller pack more often of course, but on longer trips you are forced to charge on the move.
This is now both expensive and you are dependent on the charger working correctly !.
Our previous ZS EV ( Gen 1 ) did a great job of satisfying our needs for the two years of ownership, but would I willing go back to the smaller size battery ?.
NO - The main reason why I upgraded to the LR model, was for that larger battery.
The extra features in the Gen 2 are very welcomed of course, but I would have not upgraded for just the features.
The larger battery was the biggest attraction.
Honestly, I charge to 80% at home and it consistently ( in fairly good weather conditions ) predicts a range of 212 miles.
We use the car a lot and I never find myself constantly looking at the GOM all of the time, like we did on the Gen 1 model.
I now only look at the GOM when the range status changes colour from green to amber.
Then we still have around 100+ of remaining range, which is great.
So, was the larger pack worth the extra money ?.
That’s a big yes from me !.