Balance charging

[Kayged]

With my gen1, I used to put it on charge for long periods, as I had a standard rate electricity package. Nowadays, I am on Octopus GO so it is only charged over those 4 hours. Normally, this is enough to allow some time for balancing, but of course if the car is low on battery, it may only be marginal on full charge. Is this regime good enough, or should I extend the 4 hours to 5 hours, for instance?

Before we had our 7kW charger fitted I had to use the granny charger once a month I would put it on for a second night just to make sure the battery was balanced.

 

[Jomarkh]

Before we had our 7kw charger fitted I had to use the granny charger once a month I would put it on for a second night just to make sure the battery was balanced.

How long did you leave the car SOC at 100%?

 

[Coulomb]

How long did you leave the car SOC at 100%?

Presumably they don't know or care; leaving it charge overnight the second night in a row presumably well covers it.

On my Mark 1, I balance regularly every calendar month (occasionally a few days late if I forget or there is no excess solar), and for the last year it has never balanced longer than an hour. Half an hour or less is typical. If the battery hasn't been balanced in a long time, it can take many hours.

 

[Lovemyev]

Presumably they don't know or care; leaving it charge overnight the second night in a row presumably well covers it.

On my Mark 1, I balance regularly every calendar month (occasionally a few days late if I forget or there is no excess solar), and for the last year it has never balanced longer than an hour. Half an hour or less is typical. If the battery hasn't been balanced in a long time, it can take many hours.

Can I make the guess that you are running on the original factory running software and not the BMS software update that some owners had in the U.K. for the Gen 1 then ?.
I ask, because the balance cycle times on both versions were completely different.
Original factory software, balance cycle was anything from 30 minutes to 1 hour max.
Post BMS update, I could not get my Gen1 to complete the balance in under two and a half hours.
But generally it was longer than this !.
The BMS update reduced the size of the buffer at the head of the pack, no wonder the balance cycle time increased !.

 

[Coulomb]

Can I make the guess that you are running on the original factory running software and not the BMS software update that some owners had in the U.K. for the Gen 1 then ?.

I'm 98% sure that I've had the update that you refer to. Mine has always had an unusually high pack voltage; I don't know if that has anything to do with it.

Mind you, I charge at 14 A or less from excess solar; it could be that my pack starts balancing well before I notice it. E.g. if both our cars goes to a state where it only wants 4 kW and I'm charging at 3 kW, I won't see any difference unless I'm watching the LEDs (breathing versus solid on the MG logo for the Mark 1 models). If you're charging at 6.6 kW, you will notice by the reduction in charge current.

So yes, @Jomarkh, my equalisation probably takes longer than I realise; sorry for the misinformation.

Edit to add:

Post BMS update, I could not get my Gen1 to complete the balance in under two and a half hours.
But generally it was longer than this !.

I had only had my car for a month or two when I had the update; I believe you and many others drove your cars with the older software for much longer. I think that contributed to your car needing very long balances for months.

Has your balance time settled down to a lower value by now?

 

[Lovemyev]

I'm 98% sure that I've had the update that you refer to. Mine has always had an unusually high pack voltage; I don't know if that has anything to do with it.

Mind you, I charge at 14 A or less from excess solar; it could be that my pack starts balancing well before I notice it. E.g. if both our cars goes to a state where it only wants 4 kW and I'm charging at 3 kW, I won't see any difference unless I'm watching the LEDs (breathing versus solid on the MG logo for our models). If you're charging at 6.6 kW, you will notice by the reduction in charge current.

So yes, @Jomarkh, my equalisation probably takes longer than I realise; sorry for the misinformation.

Edit to add:

I had only had my car for a month or two when I had the update; I believe you and many others drove your cars with the older software for much longer. I think that contributed to your car needing very long balances for months.

Has your balance time settled down to a lower value by now?

I do not have the Gen1 anymore, I upgraded to the Gen2 model and no it never changed / improved regarding the time taken to balance the pack after the BMS update was done.
Others who had the update, witnessed the increased time taken when balancing.
What is you pack voltage and your predicted range after a full charge and balance, with both trips reset to zero first ?.
These figures will give a pretty good indication of what software version you are running on.
This has been covered in great detail on the BMS thread.
A lot of interesting reading, but the results are pretty consistent with both sets of software versions.
Pack voltage is higher pre BMS at around 455 - 456 volts is a figure that springs to mind and 448 - 450 volts post BMS update.
Sorry, its been a while, so I maybe a little bit out on these figures.
The predicted range is different also, but without checking, I am unable to verify.

 

[Chrisjk]

Thanks everyone for all those details. Much more confident about balance charging. Indeed I hope I did some last night after reaching 100%. Is there anywhere to display state of balance, or indeed state of battery? What do the lights beside the power input socket indicate?

 

[Lovemyev]

Thanks everyone for all those details. Much more confident about balance charging. Indeed I hope I did some last night after reaching 100%. Is there anywhere to display state of balance, or indeed state of battery? What do the lights beside the power input socket indicate?

What model of the ZS EV do you have ?.
The original Gen1 or the Gen2 face lift model ?.

 

[Chrisjk]

Sorry should’ve made clear.
Gen 2 facelift LR, 14 months old
Thanks

 

[Lovemyev]

So unless you have the necessary equipment to interrogate the traction battery, then the car itself has no way of displaying the balance state of the pack, via the info unit etc.
When you refer to the “state of the battery” do you mean the general health of the pack or just the current state of charge ?.
Again - You would need done equipment like a OBD reader etc, to get detailed info on the SOH.
Of course, the current state of charge level, is shown both on the App and in the head unit.
The coloured lights in the charge port are coloured blue pre charging and pulsing green in stages, when the car is receiving a charge.
If you are charging to 100% because you require the maximum range, to conduct a long journey, don’t leave the car fully charged without using it.
This is not good practice for long term health of your pack.
For local trips, set the charge level to 80% if that suits your needs.

 

[Chrisjk]

Thanks v much
General health of the pack. People refer to degraded by use to say 97%. How do they know that?
I understand that balancing won’t happen unless the battery is already at 100%.?
Normally I have it set to 80%. I do all my charging at home, Podpoint 7kW..

 

[Lovemyev]

Thanks v much
General health of the pack. People refer to degraded by use to say 97%. How do they know that?
I understand that balancing won’t happen unless the battery is already at 100%.?
Normally I have it set to 80%. I do all my charging at home, Podpoint 7kW..

You either need an OBD unit and software that will provide a SOH ( state of health ) report of the traction battery, or you can ask the dealer to provide the readings when the car receives it annual service.
Given that your car is only 13 months old ( unknown mileage covered ) I would not be concerned TBH.
As you have a long range ZS EV with the NMC chemistry, then personally I have not seen a concrete evidence that the balance cycle commences below 100%.
The MG4 is different, with this regard.

 

[Chrisjk]

Really appreciate all your advice. Thanks

 

[profdraper]

The car balances above 100% SOC. How long it takes depends on the battery chemistry & the overall health /age /owner practices to date. Easy way to tell is in the last stages of charging, ceheck the front charging light (gen 1 or gen 2) & until it goes out, ie, from full wack charging to balancing /trickle charging. Do this once & you get an idea of how long it takes.

Personally I charge off-peak overnight & with plenty of hours there to both fully charge followed by balancing. On my current gen 2 short range ZS EV with LFP battery, this takes little time & certainly under a half hour - but then this car is regulalry balanced.

On my earlier gen 1 ZS EV with NMC battery, this took precisely 105min, every time. Those figures could also easily be verified via the WalxxBox Pulsar Plus app which shows quite a lot of detail about the charging rate & where I could see the drop from full-wack 32A charging to the trickle charge phase. Of course, you could also get up and look at the light at that time in the morning; also the iSmart app will show a little about the fact that it is still charging tho' it does not seem to delineate between charging & balancing phases.

 

[Tim Green]

Recently, I connected my car to the charger although the main battery had more charge than I thought. The dashboard displayed " connected but not charging". Does this mean it would not balance charge? In other words, will it only balance charge after a period of proper charging?

 

[Lovemyev]

It could mean a couple of things, like did you have a delay charge set up or was the charging preset level ( long range ) already achieved etc.
Answers to this will differ is its standard range or long also.

 

[peterseddon]

Had the car since May 22 (Gen 2 LRT) and to my knowledge it has never told me to, or been balanced. Does the car tell you when it needs to balance?

 

[Lovemyev]

Had the car since May 22 (Gen 2 LRT) and to my knowledge it has never told me to, or been balanced. Does the car tell you when it needs to balance?

I am assuming ( like me ) you are mostly only charging to 80% SOC because this suits the majority of your usage pattern ?.
I think it’s possible to receive a “charge from an A/C supply” warning, if the car has conducted a lot of D/C rapid charging.
To the best of my knowledge, there is no warnings to carry out a balance cycle on the long range models of the ZS EV face lift.
The standard range with the LFP battery is different and will charge and balance every single time it is placed on charge.
The driver / car has no control of setting a level lower other than 100%.

 

[Roldorf]

I also have the Long Range model and have never noticed it doing a balance charge on AC charging. It charges to 100 % and then stops.

 

[Tim Green]

My car is a gen1 and the chsrger was ready to go. In fact on connecting it did appear to charge for a very short time (say 10 seconds) before displaying "connected but not charging". But my question is, does the balancing protocol only start after a period of proper charging?