Battery charging Percentage setting

[Farnham]

I own MG 4 - SE from 2023. Earlier I could able to set battery charge limit to 80%. I noticed for some months I couldn't be able to set charging at battery health mode. I have been to dealer 3 times, they updated software but unfortunately it doesn't work. Now dealer replied that MG -4 SE, charge limit cannot be set. Any member with MG-4 SE (51kWh battery) facing similar issue?

 

[hojnikb]

Pretty sure this is standard behavior. Are you sure you had actually been able to set the 80% limit and that limit be accepted?

Because due to LFPs voltage profile, BMS has a really difficult time guessing the correct SoC, if the batttery isn't charged to 100% regularly. I suspect that' why there's no option to limit charge.

 

[Bam Bam]

We have never been able to set a charge limit on our '23 SE SR.

This feature was not enabled because there is not much benefit to it on LFP batteries.

 

[decrep]

Yes the battery health- long distance mode selection is not available on our 51kWh.

 

[Tight Git]

72 reg. SE SR here and never had the ability to set a charge limit

I'm sure @Rolfe will add to this

 

[Farnham]

Hi,
Thanks for the response.
There is a sliding bar on the dashboard that allows you to adjust the charging percentage to either battery health mode or long journey mode. However, I'm not able to select it. I am concerned about the performance and life span of the battery due to the nonfunctioning of this feature. The battery is getting charged at 100% instead of the recommended 80% limit

 

[Farnham]

Yes the battery health- long distance mode selection is not available on our 51kWh.

Could you be able to set at 80%?

 

[Farnham]

Pretty sure this is standard behavior. Are you sure you had actually been able to set the 80% limit and that limit be accepted?

Because due to LFPs voltage profile, BMS has a really difficult time guessing the correct SoC, if the batttery isn't charged to 100% regularly. I suspect that' why there's no option to limit charge.

Hi,
Thanks for the response.
There is a sliding bar on the dashboard that allows you to adjust the charging percentage to either battery health mode or long journey mode. However, I'm not able to select it. I am concerned about the performance and life span of the battery due to the nonfunctioning of this feature. The battery is getting charged at 100% instead of the recommended 80% limit

 

[siteguru]

There is a sliding bar on the screen ... but in the SE SR (51kWh) you can't actually change it. (At least I can't, and have never been able to). If you have an SE LR (64kWh) then the slide bar is actually available.

If you have an SE SR and were previously able to change that setting then that was a foible unique to your car.

 

[Farnham]

There is a sliding bar on the screen ... but in the SE SR (51kWh) you can't actually change it. (At least I can't, and have never been able to). If you have an SE LR (64kWh) then the slide bar is actually available.

If you have an SE SR and were previously able to change that setting then that was a foible unique to your car.

How are you managing to keep the charging percentage@80%?

 

[siteguru]

I'm not. I never have, and have never implied anything like that.

 

[Farnham]

I'm not. I never have, and have never implied anything like that.

It's recommended to maintain a charging percentage between 20%- 80% for the efficiency and life span of the battery. Otherwise, it will deteriorate battery life. Have you thought about battery life?

 

[siteguru]

The battery will outlive the car - even charging it to 100% each time.

I'm in the camp of "Just use the damn car and stop overthinking things".

 

[Farnham]

T

The battery will outlive the car - even charging it to 100% each time.

I'm in the camp of "Just use the damn car and stop overthinking things".

Thanks for quick response

 

[Martinonline]

The advice about charging to 80% normally is usually associated with NMC batteries. LFP batteries such as yours in the SE SR operate at a lower maximum voltage and are considered not as susceptible to high voltage stress problems. That does not mean the State of Health (SOH) of your battery will not decrease over time.

Additionally the discharge voltage curve of an LFP battery means charging to 100% gives a better estimate of range versus percentage and with the SR allows the car to balance the battery.

As @siteguru has said the battery will last much longer than the car.

If you have an home EVSE (aka charger) then you should be able to control the amount of energy (kWh) you put into the car when charging, if you want to limit the charge level.

 

[Farnham]

The advice about charging to 80% normally is usually associated with NMC batteries. LFP batteries such as yours in the SE SR operate at a lower maximum voltage and are considered not as susceptible to high voltage stress problems. That does not mean the State of Health (SOH) of your battery will not decrease over time.

Additionally the discharge voltage curve of an LFP battery means charging to 100% gives a better estimate of range versus percentage and with the SR allows the car to balance the battery.

As @siteguru has said the battery will last much longer than the car.

If you have an home EVSE (aka charger) then you should be able to control the amount of energy (kWh) you put into the car when charging, if you want to limit the charge level.

Thanks for your response. I'm using a public charging point. Sometimes use a DC charger as well.

 

[decrep]

Could you be able to set at 80%?

No, it's not possible or needed.
As others have said, the lfp battery is not so intolerant of high % charge.
A 100% charge is recommended about once a week to keep the GOM accurate.

I have read, that over a very long time, battery deterioration is less if battery is mainly operated between 40 and 80%

 

[Bam Bam]

How are you managing to keep the charging percentage@80%?

You don't - just charge up to 100%.

Only downside is that you don't get regen when you drive at 100%

 

[siteguru]

You don't - just charge up to 100%.

Only downside is that you don't get regen when you drive at 100%

The upside being that you get a chance to exercise your physical brakes to help clean the pads and discs.

 

[Hilliea]

Hi,
Thanks for the response.
There is a sliding bar on the dashboard that allows you to adjust the charging percentage to either battery health mode or long journey mode. However, I'm not able to select it. I am concerned about the performance and life span of the battery due to the nonfunctioning of this feature. The battery is getting charged at 100% instead of the recommended 80% limit

I must have inadvertently set mine to 69%. Couldn't charge car. 'Charging Complete'. I was puzzled and phoned AA. They did not point me to percentage limiter. Only when I sat there frustrated and used this community chat did I realise what had happened. AA van was cancelled before he had set off !