How to balance MG5 EV 2021 pre facelift

[paulboy]

At 5 yrs and 40,000 miles my battery at recent service check was down to 85% is that about right? Also, how do I force a balancing charge. The car has never asked me to do one.

 

[Alb]

Charge to 100% on an AC Charger and leave it connected. You'll see it consuming a few hundred Watts whilst it balances before it switches off (this may take hours).
The manual says the car will tell you if it thinks it needs a balance but I've never heard of anyone actually seeing this.
Might be a good idea to get an OBD2 reader so you can see exactly what the cell voltage range actually is.

 

[SimonomiS]

Charge to 100% on an AC Charger and leave it connected. You'll see it consuming a few hundred Watts whilst it balances before it switches off (this may take hours).
The manual says the car will tell you if it thinks it needs a balance but I've never heard of anyone actually seeing this.
Might be a good idea to get an OBD2 reader so you can see exactly what the cell voltage range actually is.

I got this alert from the car (Mag5 pre FL) the other day for the first time ever after 85k miles! There was an audio alert (the same one as when starting when ready to select a gear) and a text message on the display that very rapidly disappeared along the lines of BMS balance charge required. I thought that I've done this many times but I'm on the IOG tariff which switches on & off remotely so perhaps doesn't let this happen. I'll do a granny charge overnight and see how that goes. The alert only seems to comes on when braking to a full stop

 

[paulboy]

Thank you both. Will try using granny charger overnight.

 

[kevin ellard]

At 5 yrs and 40,000 miles my battery at recent service check was down to 85% is that about right? Also, how do I force a balancing charge. The car has never asked me to do one.

As others have said, just leave it charging after it gets to 100% and it will balance itself. 85% seems suspiciously low though. I think that at 5 years old most people would expect it to still be over 90% unless badly treated.

 

[5teep]

My first MG5 pre fL was 98% on 45k miles at a bit over a year old. Charged every day on AC with small DC charges often. Maybe it's also an age thing? I don't know. Never worried about balancing, I just figured the car would take care of it.

 

[MickeySw]

At 5 yrs and 40,000 miles my battery at recent service check was down to 85% is that about right? Also, how do I force a balancing charge. The car has never asked me to do one.

85% seems low, however it would not be the first time that the wrong value was given.

An easy way to check SoH is to charge to 100% and reset trip data afterwards, the range should show WLTP - degradation..

 

[Jomarkh]

Thank you both. Will try using granny charger overnight.

It may take a few times to recover a bit of SOH percentage. Try an do it monthly.

 

[MickeySw]

It may take a few times to recover a bit of SOH percentage. Try an do it monthly.

Balancing alone won’t do much for SoH, you need to re-calibrate the BMS, I.e. discharge below 10% then AC charge without interruptions to 100% and let it plugged in until the car stops the process.

 

[decrep]

Balancing alone won’t do much for SoH,

I guess you mean reported state of health?????
calibrating the BMS shouldn't affect actual SOH

But balancing the cells should improve SOH but may not be fully reflected in reported SOH until BMS is calibrated.
Does that sound right???