Battery Equalisation/Balancing MGS5 second attempt

[Data]

Yes, indeed it is very confusing as so many people disagree on how to do the equalisation charge. I will say that Octopus & MG did both tell me to turn off smart charging before doing an equalisation charge, my dealer to. As soon as I did my car started equalising correctly. It will now equalise at any soc whereas previously it would not. Just spoken to my installer & he too has confirmed (again) I must turn off smart charging. And as I suspected, it's down to the configuration of the wall box & car. If the wall box is listed as the primary device with smart charging activated, the BMS can't control the equalisation. It seems it's that simple. And this in part actually explains why so many of us have conflicting views on the subject. Anyway, I can & have been equalising ok. No issues. And today it seems we've learned something else. All good.

 

[LenEV2016]

Yes, indeed it is very confusing as so many people disagree on how to do the equalisation charge. I will say that Octopus & MG did both tell me to turn off smart charging before doing an equalisation charge, my dealer to. As soon as I did my car started equalising correctly. It will now equalise at any soc whereas previously it would not. Just spoken to my installer & he too has confirmed (again) I must turn off smart charging. And as I suspected, it's down to the configuration of the wall box & car. If the wall box is listed as the primary device with smart charging activated, the BMS can't control the equalisation. It seems it's that simple. And this in part actually explains why so many of us have conflicting views on the subject. Anyway, I can & have been equalising ok. No issues. And today it seems we've learned something else. All good.

If I really want to make sure it's done I charge to 100% over night then the next morning hook up the granny charger, it hardly draws any power, so not using loads of power

 

[MickeySw]

Does equalisation charge have to be done from a low percentage SOC?

The short answer is no, after 100% SoC is reached (AC charging only) the BMS checks if there is a voltage difference between the individual cells and (only if there is) starts the balancing process.

Starting @ low SoC is done for a different reason altogether (calibrating the BMS).

The video below explains the principle quite nicely although some specifics do not apply to MG models

 

[Data]

If I really want to make sure it's done I charge to 100% over night then the next morning hook up the granny charger, it hardly draws any power, so not using loads of power

The only issue with doing that is that a full equalisation & balance needs to be uninterrupted & done from a low state of charge (below low battery warning) continuously up to 100% & then letting the BMS do it's thing to equalise. Again it was MG that said to me the charge must not be interrupted. Apparently if interrupted the BMS becomes disengaged from the process. What you may be seeing after plugging in your granny is just an initial minor charge which only continues for a few moments or a minute or two which almost certainly won't be a balance/equalisation. It would be interesting to analyse that more closely.

 

[LenEV2016]

The only issue with doing that is that a full equalisation & balance needs to be uninterrupted & done from a low state of charge (below low battery warning) continuously up to 100% & then letting the BMS do it's thing to equalise. Again it was MG that said to me the charge must not be interrupted. Apparently if interrupted the BMS becomes disengaged from the process. What you may be seeing after plugging in your granny is just an initial minor charge which only continues for a few moments or a minute or two which almost certainly won't be a balance/equalisation. It would be interesting to analyse that more closely.

These batteries are not that fragile and owners are unlikely to see major issues with them in their ownership.
People charge there NMC batteries to 100% everyday and see no issues.

LFP batteries like a low state of charge to 100% charge every month, less important for nmc

 

[Data]

These batteries are not that fragile and owners are unlikely to see major issues with them in their ownership.
People charge there NMC batteries to 100% everyday and see no issues.

LFP batteries like a low state of charge to 100% charge every month, less important for nmc

Yes!