Balancing battery knowing when completed

[billybonfire3]

I've left my car charging on a 7kw charger a number of times well past the 100 percent battery charge but even after more than an hour there is still a trickle at 1.93kw. wouldn't this stop when battery balanced or would there always be a trickle?

 

[Davemac278]

Balancing can take 1-2 hours. If you don't balance regularly or had old BMS issues it can easily take longer than 2 hours to complete.

 

[Kithmo]

The battery is balanced when the trickle stops altogether.

 

[Jomarkh]

I thought the battery balance was done between 300-500w. 1.93kW isn't really a trickle

 

[rbpasapera]

I thought the battery balance was done between 300-500w. 1.93kW isn't really a trickle

Yes, mine does it at 0.3-ish kW.

 

[Thebiglad]

hi all, I have a 2021 ZS EV and in it's handbook it states that it can take up 27 hours on the charger for the battery to be fully rebalanced.

Just on a related point, in the last 10,000 kms I have only charged once or twice away from home, the vast majority of charging is done via the Granny cable on a std. 16 amp socket and I have never been asked to "balance the battery".

 

[Elec Car Aust]

hi all, I have a 2021 ZS EV and in it's handbook it states that it can take up 27 hours on the charger for the battery to be fully rebalanced.

Just on a related point, in the last 10,000 kms I have only charged once or twice away from home, the vast majority of charging is done via the Granny cable on a std. 16 amp socket and I have never been asked to "balance the battery".

Same here. On the Gen 1 ZS the MG badge light turns off when fully balanced. If it is on fully (not flashing) it is balancing.

 

[Les burrows]

Hi,fully charged and balanced my MG5 last night on my Zappi 2 on an Eco setting which charges T 1.4kw when the suns gone down, so the graph below shows what the charger did from midnight last night Tuesday 05/07 until this morning, it stopped charging at 100% and then balanced for around 2 hours before switching off, I have driven about 140 miles in the car today and when I got home it was showing 42% remaining, so I have again stuck it on a trickle charge over night, which should take it up to around 80% for tomorrow morning, I will stop it there as I won’t be going any real distances tomorrow.

looking at the graph it appears it took around 1h:50 mins to do the balancing once it got to 100% hope this might be of help

Edit
the picture above was from last night here now this morning is a picture of what has gone on over night Zappi now has been charging in Eco+ mode and the car is now charged to 82%.
So as you can see the Zappi has fed nice and slowly fed the car 20.02KW over approximately the last 14 hours and now I have stopped the charge has that will do me for a couple of days I would think
Les

Sent from my iPad

 

[Lovemyev]

hi all, I have a 2021 ZS EV and in it's handbook it states that it can take up 27 hours on the charger for the battery to be fully rebalanced.

I find this strange, as I was of the opinion that the car would only try to balance the battery for up to about 10 hours, then if this was unsuccessful it would stop and then retry the next time it was asked to perform a balance.
It has been found that the balance cycle tends to be a shorter time scale, when the car is running on the original software, over the cars with the BMS update introduced on the 15th Jan 2021.
Generally a balance cycle on the original software would take anything from as little as 45 minutes to one and a half hours.
With the BMS update applied, regular cycle times can vary massively, but are never shorter than about two and a half to three hours minimum !.
It is thought, that this is a result of increasing the size of the buffer at the head of the battery on the BMS update.
My previous ZS EV Gen 1 had run on the original software firv12 months, then another 12 months on the latest software due to the BMS upgrade,
Balance cycles will only commence after 100% SOC has been reached.
With the BMS update applied.
When the SOC has hit 100% it will commence the balance cycle.
It starts by pulling around 750 Watts of power from a A/C supply, then it will reduce to 500 Watts.
It will continue to throttle back again closer to the end of the cycle, when it finally hits about 175 Watts.
Soon after this, the balance will complete and the car will automatically shut down the wall box or the Granny unit.
Balance cycle times are increased post BMS update, that is for sure !.

 

[profdraper]

FWIW, my 2021 ZS EV takes 105mins to balance every time & is very predicatble. This I assume is because of my other battery discharge and charge useage, often from 20% to 80% and exclusively on 7kW home charger. Sometimes up to 90% & from a higher battery charge, but I tend to mix that up a little.

The main point about balancing - this is finished only when the MG badge light does out. Otherwise, do not interrupt or cancel the balancing phase. Others indicate that this may result in similar battery degredation issues or problems associated with the earlier botched OBD version.

In owner discussions elsewhere in the UK and in AU, there has been quite a bit of talk about not taking any notice and 'just charging up all the time to 100% via granny or 7Kw overnight & basically ignoring this. Problem is, at 100% the MG goes into balancing mode automatically & so you need to take control of that, allow for the extra balance time, & don't artifically stop this.

Hence, I go for 90% most of the time; if 100%, then allow for balancing time & the car's happy.

 

[Kithmo]

I find this strange, as I was of the opinion that the car would only try to balance the battery for up to about 10 hours, then if this was unsuccessful it would stop and then retry the next time it was asked to perform a balance.
It has been found that the balance cycle tends to be a shorter time scale, when the car is running on the original software, over the cars with the BMS update introduced on the 15th Jan 2021.
Generally a balance cycle on the original software would take anything from as little as 45 minutes to one and a half hours.
With the BMS update applied, regular cycle times can vary massively, but are never shorter than about two and a half to three hours minimum !.
It is thought, that this is a result of increasing the size of the buffer at the head of the battery on the BMS update.
My previous ZS EV Gen 1 had run on the original software firv12 months, then another 12 months on the latest software due to the BMS upgrade,
Balance cycles will only commence after 100% SOC has been reached.
With the BMS update applied.
When the SOC has hit 100% it will commence the balance cycle.
It starts by pulling around 750 Watts of power from a A/C supply, then it will reduce to 500 Watts.
It will continue to throttle back again closer to the end of the cycle, when it finally hits about 175 Watts.
Soon after this, the balance will complete and the car will automatically shut down the wall box or the Granny unit.
Balance cycle times are increased post BMS update, that is for sure !.

In my handbook it actually says 22 hours on the granny including charging to 100% from the low battery warning, not just for the balancing.

 

[Kithmo]

ISTR around the duff BMS saga time, there was a suggested method of partly balancing the battery by leaving the car switched on and parked up in Ready mode.
Did anybody actually do this and did it work ?

 

[Lovemyev]

ISTR around the duff BMS saga time, there was a suggested method of partly balancing the battery by leaving the car switched on and parked up in Ready mode.
Did anybody actually do this and did it work ?

I think some of the dealers used this method.

 

[hmadsen]

Mine also goes on for quite some time after it gets to 100%

The "Charging will finish" in the app is absolutely terrible at predicting the finish time.

It will go on at full speed charging until it reaches 100% and then it will just state that charging will finish at the time the phone clock shows, and if you update 1 minute later it will show that time.

Mine sometimes does this for up to 45 minutes, before going into balancing. When it is truly finished it will send a signal to the charger i have, that the battery is full, and the charger will say Battery at 100%

 

[MichaelJHunt]

From the manual for the MK2 ZS EV

So for the LR ZS EV it says 11.5 hours. That is from empty to full and includes balancing of the cells.

The actual balancing process doesn’t take too long. About 10 hours to charge the battery pack and 1.5 hours to balance the cells.