Charging Routine

[Alb]

Had the car for a month now and I don't think the state of charge has ever dropped below 80%.
I'm not doing any long journeys so do you think it would be better for the battery if I ran it down and maintained it a much lower state of charge?
I'm only using the Granny at the moment so charging rate has only ever been low.

 

[JohnB]

Anything between 50% and 80% is supposed to be the "ideal" level for the cells to be kept for longevity. That is cell level, not the reported pack level. MG try very hard to keep your worst intentions for severely damaging the pack. If, like me, you generally do shorts journeys with the occasional long run you won't go far wrong keeping it around 75%. A Tesco's free charge a couple of times a week is generally enough for me and so my SOC hovers around the 70% mark. I then can get to 100% on the granny when I know I'm doing a run the next day.

 

[Adee]

With the granny charger you always have the "filling station" on-hand at home so it seems daft not to plug it in every night when you get home. But I resist the temptation to recharge every night and usually let it drop to 60-70% which means that 7hrs on Economy 7 will more-or-less top it right up again. Less than 70% and you need to repeat for 2nights to get a full charge (approx 30% charge per night). I occasionally let it get below 50% to cycle the battery differently and it's currently sitting on 35% after a long run today, ready to charge over the next 2 nights. It seems to "go against the grain" to let it drop too low (especially as I don't really plan my days ahead). No idea if I'm doing the right thing or not TBH

 

[PaulR]

Had the car for a month now and I don't think the state of charge has ever dropped below 80%.
I'm not doing any long journeys so do you think it would be better for the battery if I ran it down and maintained it a much lower state of charge?
I'm only using the Granny at the moment so charging rate has only ever been low.

I only have the granny charger and a 7kw charger at work. Generally I run it down to below 50% and then stick it on at work for a couple of hours. I only top to 100% if I know I have a long journey ahead of me or a few 40+ mile journeys a few days. I quite like the granny charger and find it as much as I will ever need as my annual mileage is around 6k.

 

[n8sail]

Per the manual, you should top-off completely and allow for cell balancing ('Equilisation Charging' in the manual) at least once a month... MG in Thailand said I need to go to the dealership and do this once a WEEK on their 'slow charger'! Yeah, right...

Anyways, you know this has occurred when you give enough time for 100% charge on either granny or 7kw AC charger and the status on the info screen says (IIRC) "100% SOC, Charger Connected, Uncharged".

It will supposedly warn you "Please charge for BMS Balance" if you don't do this often enough. I have not seen this before, let me know if anyone here has...

Other than that, as stated above somewhere between 50% and 80% state of charge will help longevity for most Lithium-based battery chemistries.

 

[drewpost]

Does anyone know what the battery chemistry used in the MG5 is? Is it LFP? I find it odd that there's seemingly no "max charge" setting like on my Tesla so you can tell it to only charge up to 70/80%

 

[n8sail]

I was wondering the same thing... only thing I can find is that it is a "Ternary Lithium Ion Battery" which means it uses combination of lithium nickel cobalt manganate (Three metals hence "Ternary") as positive electrode and graphite as the negative electrode material. They are different from Lithium Iron Phosphate in that they start burning at a lower temperature, so a little less safe, but they have higher specific energy than LiPO4 batteries.

LiPO4 is probably better for the environment as there are no precious metal elements used... but what did we expect in a car coming from China?

I'm very interested to know the cell type/brand/size... anyone ever figured that part out?

 

[Adee]

LiPO4 is probably better for the environment as there are no precious metal elements used... but what did we expect in a car coming from China?

Errrrr...... coal powered batteries?

 

[BarryH]

I was wondering the same thing... only thing I can find is that it is a "Ternary Lithium Ion Battery" which means it uses combination of lithium nickel cobalt manganate (Three metals hence "Ternary") as positive electrode and graphite as the negative electrode material. They are different from Lithium Iron Phosphate in that they start burning at a lower temperature, so a little less safe, but they have higher specific energy than LiPO4 batteries.

LiPO4 is probably better for the environment as there are no precious metal elements used... but what did we expect in a car coming from China?

I'm very interested to know the cell type/brand/size... anyone ever figured that part out?

LiPO has a lower power density than Lithium-ion (LiON) chemistry. LiPO are great for static battery storage and you'll find them widely used for this purpose. Each manufacturer has their own chemistry and has them constantly under development and there is a push to get Colbolt Free chemistries working well enough for high volume LiON automotive applications without compromise of range, reliability and longevity. There was talk of Tesla in China using LiPO in certain Model 3 models but they would have a lower range because of the lower power density (ie fewer KWh stored in the available space) but would be cheaper to produce.

 

[BarryH]

Had the car for a month now and I don't think the state of charge has ever dropped below 80%.
I'm not doing any long journeys so do you think it would be better for the battery if I ran it down and maintained it a much lower state of charge?
I'm only using the Granny at the moment so charging rate has only ever been low.

LiON batteries in EVs have an ideal SoC range the should be operated and if you are leaving a car parked up and not driven for long periods then the chemistry suggests that 50% would be ideal. When shipped from the factory they are shipped with something like 60% I believe I've read somewhere on a forum to allow for slow discharge to around 50%. However in use regularly charging to 80% is fine and it isn't recommended to charge to 100% unless you are going to use the car within the next few hours OR you are doing a Balancing Charge when you leave the car on charge for a few hours beyond 100% SoC. What you need to remember is that the "Available" Charge or range is not the full capacity of the battery and MG has a buffer above what you see as 100% Full Charge for a number of practical purposes. 1, degradation so that throughout the warrantied life of the car the full charged range can be maintained. 2, so the when driving from fully charged there is some capacity left to absorb the electricity generated from Regenerative Braking (KERS) and 3, so that when the owner fully charges the car, the battery cells are not 100% charged which stresses them and would reduce their longevity.
When driving long distances its fine to take the battery down to a low SoC and then recharge at Rapid Charger but it's not recommended to take it down to say 10 miles or below and then leave the car without recharging as although MG have ensured that at Empty there is still some charge remaining it is as damaging to LiON chemistry to be kept at a very low State of Charge (SoC) as it is to be kept at a very high SoC. Personally, on a long hack, I'll begin at 100% and rapid charge at 10% - 15% up to 80%-90% and aim to arrive with 25% - 50% SoC.
A final note on Balance Charging. I was told on good authority that the MG won't balance Charge on a Rapid Charger nor will it on a Granny Charger. Balance charge has to be on a 7kW charger and once 100% SoC is reached the car chargers at about 300 Watts and needs from between 30 minutes and 6 hours to complete the Balance Charge. If the battery hasn't balance fully after 6 hours then charging will stop. However, cell Balancing will also happen as the car is driven from 100% SoC down to about 97% after which further charging to 100% will allow further cell balancing to take place. Much of the information on balancing came to light after the BMS (Battery Management System) problems at the end of 2020 and early in 2021 and the faulty BMS Update.

 

[JohnB]

.... I was told on good authority that the MG won't balance Charge on a Rapid Charger nor will it on a Granny Charger. Balance charge has to be on a 7kW charger ....

Not quite. The granny charger is using the onboard 7kW charger, and so will provide a balance charge. You're right about rapid though, that wont.
We might have a new sport here - "Balance on your granny".

 

[Adee]

You can always rely on Granny

 

[Tiny Tom]

Leaving the granny charger on til the badge light goes off is brilliant. You get full charge with 163 on GOM and 456volts. In good weather and sensible driving you can actually get around 200 miles.

 

[Lovemyev]

Balancing of the HV pack can only be achieved on either a 7.0 kw wall box or the slower Granny unit.
Not on a rapid charger !.
Your reported voltage on the HV pack after a full charge / balance, will depend on which BMS software package you are running on.
The latest BMS update released on 15th Jan 2021 to rectify the “Buggy” software updates, will see a voltage on the pack of between 448 - 450 volts.
With a maximum predicted range of around 163 miles on the GOM in the default normal mode.
This voltage figure should be seen after BOTH trip meters have been reset to zero and when booting up the car with everything turned off and with no pressure applied to the foot brake when doing so.
If I remember correctly, the voltage on the pack after a full charge on the original factory OEM software package, was 456 volts,
The latest update appears to have increased the size of buffer at the upper end of the HV battery and therefore this can be seen buy the reduced upper voltage of the pack when fully charged.
Down from around 456 to 448 / 450 volts.
As a result, Regen can be now be felt much earlier ( due to the extra space in the HV battery ) and is more linear from a much earlier stage now.

 

[Petriix]

Leaving the granny charger on til the badge light goes off is brilliant. You get full charge with 163 on GOM and 456volts. In good weather and sensible driving you can actually get around 200 miles.

Wrong forum. The MG5 doesn't have a badge light. And I'd be pretty impressed if you managed to actually drive a ZS 200 miles between charges. Do you have any evidence of this actually happening?

 

[Petriix]

Balancing of the HV pack can only be achieved on either a 7.0 kw wall box or the slower Granny unit.
Not on a rapid charger !.
Your reported voltage on the HV pack after a full charge / balance, will depend on which BMS software package you are running on.
The latest BMS update released on 15th Jan 2021 to rectify the “Buggy” software updates, will see a voltage on the pack of between 448 - 450 volts.
With a maximum predicted range of around 163 miles on the GOM in the default normal mode.
This voltage figure should be seen after BOTH trip meters have been reset to zero and when booting up the car with everything turned off and with no pressure applied to the foot brake when doing so.
If I remember correctly, the voltage on the pack after a full charge on the original factory OEM software package, was 456 volts,
The latest update appears to have increased the size of buffer at the upper end of the HV battery and therefore this can be seen buy the reduced upper voltage of the pack when fully charged.
Down from around 456 to 448 / 450 volts.
As a result, Regen can be now be felt much earlier ( due to the extra space in the HV battery ) and is more linear from a much earlier stage now.

The MG5 has a fully charged voltage of 405v.

 

[BarryH]

The MG5 has a fully charged voltage of 405v.

The battery pack in ZS and MG5 are both quite different.

 

[Cocijo]

That’s interesting. Do you know how they are different apart from the size?

 

[BarryH]

Interesting point to note is that the Facelift ZS LR and SR have completely different battery chemistry which requires a completely different Charging Routine. The First-Gen ZS, and Facelift LR both have the Cobalt containing Lithium-Ion (Li-Ion) chemistry which for battery health shouldn't he left charged at 100% and ideally for battery longevity should be charged only to 80% for daily driving reserving the 100% for charging up before longer road trips.

The Facelift ZS SR with 51 kWh battery has Cobalt free Lithium Iron Phosphate (LiFePo4) chemistry also known simply as LFP and this ideally SHOULD be charged regularly to 100%. This is a similar chemistry to that found in Home Storage Batteries and is clearly an advantage to charge to 100% at the start of every day.

Personally I think LFP is great for those transitioning from ICE and who are used to the idea of filling up their tank. To plug in at night irrespective of the State of Charge (SOC) and to know you have a full 51 kWh of charge at the start of the day makes life so much easier and predictable. Knowing that you aren't abusing the battery and shortening it's life or accelerating the car's depreciation is also good to know. It is also good to know that LFP are Cobalt Free.

LFP is not without its drawbacks thought, but less so for us than those in much colder climes, because LFP can not be charged as quickly at lower temperatures. So this could mean slower overnight charging at home but as the pack will be warmed when driving it shouldn't be too noticeable en-route at the Rapid Charger. This may account for the higher voltage of the SR battery Pack on the LFP SR compared to the LR's Li-Ion Battery Pack to mitigate this since you can charge a higher voltage battery faster. LFP also dose have a lower Power Density, that is fewer kWh compared with Li-Ion of the same pack volume which is why the LR still has the Li-Ion chemistry. LFP batteries are increasing in Power Density and Tesla is it would seem to be rolling out LFP to more of its model rage but not the Performance variants because Li-Ion does still have the edge on shear power delivery needed for expensive high acceleration and performance.

 

[Cocijo]

Very informative - thank you. Do you know why they should be charged to 100%? I guess in a none technical sense i’ve aleays thought a fully charged pack puts stress on the cells and should not be left for a long time in this state - how is this not the case with LFP do you know? So I guess it’s ok to leave your car fully charged for a long time with LFP?