MG4 discharge curve

[BingBong]

Hi, i noticed that when i charge my 64kWh to 100%, the discharge is not normal. For example, at 100% a 20km trip can take 4%.

And from 80% the same trip can take 7-8%.

This is normal? Should I do an SOH test?

 

[Martinonline]

Use of the buffer zone above 100%? BMS not good at calculating percentages near max voltage?

 

[BingBong]

Use of the buffer zone above 100%? BMS not good at calculating percentages near max voltage?

This is what i think., if it use the buffer its bad. Unfortunately even if there is a fix the dealer will not updated my BMS because he don't know ehat is that ?.

I just want to make sure that this is normal behavior of the BMS/battery.

 

[siteguru]

Are both trips exactly the same routes and in the same weather conditions?

 

[Martinonline]

Unfortunately it can be difficult to explain the differences. It can be that you used the car shortly after charging to 100% and the battery was warm whereas you left the car at 80% and it was colder. You may have had different headwinds on your journeys or your average speed was different. The battery usage increase significantly with speed.

Have you calibrated the BMS with a 10% to 109% charge recently? Do you let the car balance when charging to your set level?

 

[siteguru]

Your finger slipped ... 109%?

 

[Robf]

I never get into rabbit holes like that, I really just dont care. If the car started to show signs of overall lesser mileage I would then do something (probably a balancing charge). Otherwise I charge, get in and enjoy the drive. But each to their own.

 

[BingBong]

Are both trips exactly the same routes and in the same weather conditions?

Same weather conditions (sunny) and same route but in the opposite way (home-airport, airport-home without stop). Road is pretty flat.

Unfortunately it can be difficult to explain the differences. It can be that you used the car shortly after charging to 100% and the battery was warm whereas you left the car at 80% and it was colder. You may have had different headwinds on your journeys or your average speed was different. The battery usage increase significantly with speed.

Have you calibrated the BMS with a 10% to 109% charge recently? Do you let the car balance when charging to your set level?

Same day, without stop/parking. I did 10 to 100% one month ago. I don't know if it did blance but i let the car be in the charger 1.5 hour after 100%.

Also this charge was 40-100%.

I never get into rabbit holes like that, I really just dont care. If the car started to show signs of overall lesser mileage I would then do something (probably a balancing charge). Otherwise I charge, get in and enjoy the drive. But each to their own.

You right, but if it's a problem and not normal i will mention that in the service appointment.

 

[Martinonline]

Your finger slipped ... 109%?

These phone keyboards are just too small!!

 

[fnegroni]

Hi, i noticed that when i charge my 64kw to 100%, the discharge is not normal. For example, at 100% a 20km trip can take 4%.

And from 80% the same trip can take 7-8%.

This is normal? Should i do SOH test?

The only reliable way to test this is to use an OBD2 dongle and read the exact power consumed in real time.
However, there’s a consumption chart on the infotainment screen that will show you the power consumption profile plus how many kWh were used and regenerated since start and since last charge. Those figures are rounded down unfortunately, but should be accurate enough for your purpose.

 

[BingBong]

The only reliable way to test this is to use an OBD2 dongle and read the exact power consumed in real time.
However, there’s a consumption chart on the infotainment screen that will show you the power consumption profile plus how many kWh were used and regenerated since start and since last charge. Those figures are rounded down unfortunately, but should be accurate enough for your purpose.

Any OBD2 should work?

 

[fnegroni]

Any OBD2 should work?

Buy a reliable OBD2 dongle: the list by the CarScanner app developers is quite comprehensive and will help you decide which dongle to buy.
Bear in mind a Bluetooth LE dongle will have a wider compatibility but its performance might be slightly compromised in certain real time applications.

 

[YaR]

This is more likely a software issue, isn't it? I've noticed that I can sometimes get up to 10-15 miles at 100% before it ticks down to 99%. I don't worry. I find the battery range pretty consistent with the WLTP ratings at this time of year, subject to use of AC, driving conditions, etc.

 

[BingBong]

This is more likely a software issue, isn't it? I've noticed that I can sometimes get up to 10-15 miles at 100% before it ticks down to 99%. I don't worry. I find the battery range pretty consistent with the WLTP ratings at this time of year, subject to use of AC, driving conditions, etc.

Exactly my problem. I hope this software issue not hurt the battery by let u use the buffer.