Equalisation charge

[Ozzie1989]

Just in case it causes confusion and those new here with MG5s start panicking, the above conversations about BMS updates relate to the ZS and you don't need to visit your dealer tomorrow!

To bring this back onto track for the MG5, and compare to the ZS, what's the average time for an MG5?

 

[Delboy102000]

One feature of the new Jan 2021 BMS was too reduce the pack voltage down from 255 - 256 volts down to 249 - 250 volts.
This is indeed completely normal !.
Owners are now reporting longer balance times as a result of the update.
This COULD be because of increased space at the top of the pack.
It MAYBE the reason why balancing now takes longer than it did before.
In the first 12 months of ownership, I would only charge to 100% IF I needed to make a longer trip.
In most cases, I would only charge to around 80% in attempt to be kind to my pack.
The pack could well have been out of balance prior to the update ???.
Charging every time to 100% after the update, felt a little like chasing a magical unicorn ? to be honest.
Trying to hit the magical 250 volts and the suggested 163 miles of range should be expected after the update.
These are “Headline” ideal base line figures.
After 12 months of receiving the update, I have now found that the BMS has had time to evaluate the actual SOH of the pack, and is now regularly reporting a more true and genuine figure of the predicted mileage reported on the GOM.
It has taken a few months to analyse and account for any battery degradation in the pack.
When the BMS is installed it wipes out any historical data and is given a base line to work from.
Then from this baseline, it will start to figure out what is going on with the pack.
If you car received the BMS update and you are a low usage case, it is likely to learn what is going on fairly quickly.
If you are a higher usage case, then it is going to take a little longer for results to be more consistent.
My car is over two years old and has covered 18,000 miles.
It NOW consistently reports 249 volts and an predicted range of 145 miles after a full charge and balance.
This indicates a battery SOC of around 94ish percent .

Hi,
Surely you mean 449 not 249!?

 

[Lovemyev]

Hi,
Surely you mean 449 not 249!?

Sorry for the typo, I had been updating my wall box prior to responding to the post, with a new Wi-Fi relay and my mind was still hoked into 240 volts !.
I have amended the thread(s) now, thanks for letting me know .

 

[AnonymouseDriva]

To bring this back onto track for the MG5, and compare to the ZS, what's the average time for an MG5?

well, for me it's next to nothing.

To put that into context though, I'm on Octopus Go faster so only charge for 3 hours a night. That puts in around 30% (consuming around 21KWh). We only bother plugging it in whenever it's below 50%, and generally use 10-15% on school / work runs.

I don't balance it on a 'schedule' as such, but to charge it to 100% and allow it to balance if I'm going on a longer trip. I've had the car since Sept 1st 2021* and have charged to 100% maybe four or five times. Ernie has only spent 25 mins of his life on a rapid. Everything else is on my Hypervolt or a granny.

Looking at the hypervolt charging graph though, I see the charge rate drop off as it approaches full (curving down to about 3-4Kw before stopping altogether if memory serves me right). I was then expecting to see it run for a bit at around 300w to balance, but if it does, it's not long enough for it to show as such. Maybe it's averaged over 15 minute slots and there was some balancing as part of the last 15 mins? Either way, there's no obvious balancing time. I've never caught it balancing either by looking at the display. After the charge, it's happily at 406v (which I believe is the expected voltage for a balanced 5LR)

I guess the balancing time varies based on use case though. I drive fairly gently, my battery SOC generally tends to be between 35-85% and I almost never need to charge away from home so avoid most of the factors that would knock a battery far out of balance. Couple that with the frequency of my full charges, I suppose it's not too surprising that balancing is barely noticeable for me.

*Edit - got the year wrong! must have been all that partying last year...

 

[Ozzie1989]

Thanks that's really useful ?

 

[bwanamdevu]

well, for me it's next to nothing.

To put that into context though, I'm on Octopus Go faster so only charge for 3 hours a night. That puts in around 30% (consuming around 21KWh). We only bother plugging it in whenever it's below 50%, and generally use 10-15% on school / work runs.

I don't balance it on a 'schedule' as such, but to charge it to 100% and allow it to balance if I'm going on a longer trip. I've had the car since Sept 1st 2022 and have charged to 100% maybe four or five times. Ernie has only spent 25 mins of his life on a rapid. Everything else is on my Hypervolt or a granny.

Looking at the hypervolt charging graph though, I see the charge rate drop off as it approaches full (curving down to about 3-4Kw before stopping altogether if memory serves me right). I was then expecting to see it run for a bit at around 300w to balance, but if it does, it's not long enough for it to show as such. Maybe it's averaged over 15 minute slots and there was some balancing as part of the last 15 mins? Either way, there's no obvious balancing time. I've never caught it balancing either by looking at the display. After the charge, it's happily at 406v (which I believe is the expected voltage for a balanced 5LR)

I guess the balancing time varies based on use case though. I drive fairly gently, my battery SOC generally tends to be between 35-85% and I almost never need to charge away from home so avoid most of the factors that would knock a battery far out of balance. Couple that with the frequency of my full charges, I suppose it's not too surprising that balancing is barely noticeable for me.

Oops! “ I've had the car since Sept 1st 2022! “ Is this a similar situation to ‘Back to the Future’?

 

[AnonymouseDriva]

Oops! “ I've had the car since Sept 1st 2022! “ Is this a similar situation to ‘Back to the Future’?

Hah! What year is it again? I think I lost a couple recently...

 

[Dino]

I’ve just attempted a balancing charge in my MG5 SR. Looking at the app for the charger the kWh rate dipped for about the last 30 minutes of charging before switching off as fully charged. The dash display shows (after reset) the HV is at 404v, 100% and the GOM is 180miles in normal

 

[profdraper]

Courious to know if this 'six week' recommendation for battery rebalancing has anything to do with total Ks driven. eg, say I only drive urban 5k per year vs. someone who does 20k per year with mixed long range and short hops ... Logically, I would have though little driving use per month would have not had as much an imapct on the necessity for re-balancing, but this may well be incorrect?

 

[Jomarkh]

Hi, the book says monthly not 6 weeks.
I think it is more about what type of EVSE you use. Fast chargers are kinder to the battery but rapid units hit the battery hard and the battery cells are put out of balance by holding different voltages.
Are you planning on keeping the car any length of time?

 

[Lovemyev]

It would appear that the balance time after a full charge is fairly small on the MG5 then?.
Probably indicating that the buffer at the top of the pack is fairly small also.
When charging from a wall box, anything below about 97% SOC and the car will pull around 7.0kw’s.
Above this SOC the car will throttle back the demand down to about 3.6 Kw’s.
At 100% it will then enter the balance cycle, throttling down the demand again to about 500 Watts.
It will do this until very close to finishing the balance, when it will drop to roughly 175 Watts.
Very soon after this, it will complete the balance and automatically disconnect the contactor in the wall box and return it to the standby state.
I have witnessed this behaviour on my home energy monitor, when charging our ZS EV.
I guess it will be very similar on the 5 but as the balance cycle is much shorter, you will have to be vigilant to catch it in the act ?.

 

[SDP79]

well, for me it's next to nothing.

To put that into context though, I'm on Octopus Go faster so only charge for 3 hours a night. That puts in around 30% (consuming around 21KWh). We only bother plugging it in whenever it's below 50%, and generally use 10-15% on school / work runs.

I don't balance it on a 'schedule' as such, but to charge it to 100% and allow it to balance if I'm going on a longer trip. I've had the car since Sept 1st 2021* and have charged to 100% maybe four or five times. Ernie has only spent 25 mins of his life on a rapid. Everything else is on my Hypervolt or a granny.

Looking at the hypervolt charging graph though, I see the charge rate drop off as it approaches full (curving down to about 3-4Kw before stopping altogether if memory serves me right). I was then expecting to see it run for a bit at around 300w to balance, but if it does, it's not long enough for it to show as such. Maybe it's averaged over 15 minute slots and there was some balancing as part of the last 15 mins? Either way, there's no obvious balancing time. I've never caught it balancing either by looking at the display. After the charge, it's happily at 406v (which I believe is the expected voltage for a balanced 5LR)

I guess the balancing time varies based on use case though. I drive fairly gently, my battery SOC generally tends to be between 35-85% and I almost never need to charge away from home so avoid most of the factors that would knock a battery far out of balance. Couple that with the frequency of my full charges, I suppose it's not too surprising that balancing is barely noticeable for me.

*Edit - got the year wrong! must have been all that partying last year...

Thank you for this. I too am with Octopus Go a few questions :-
1) It is 4hrs a night for me -0030 to 0430 - is this just a typo?
2) How do you manage to limit the charging to this amount of time? As far as I am aware there is no facility with the MG5 to set timing of charge. Do you set the charger to turn off after 3 or 4 hours?
3) There seems to be no system to regularly do a balance charge - ie you cannot set the car to perform this task so how do you have a balance schedule if it is totally random? There seems to be several comments on here about setting a balance charge - can you please advise as to how this is done or am I just reading this incorrectly?

For information I always charge to 100% - as I have no way of limiting the charging amount or time period - that I know of. Secondly I have never used any rapid chargers. Yet my car goes in to balancing charge at various unpredictable intervals and can take from around 2 hrs to 12hrs.

Many thanks for your help

 

[Jomarkh]

Hi, there is a difference between Go and Go faster. Go is 4 hour go faster is 3,4 or 5 staring at different times.
If you get a smart EVSE like the Ohme from Octopus Energy then you set that for you cheap tariff.
To balance charge just leave it connected the car takes care of the charging dropping the power down from 7.5kw to about 300-500w.
How do know it takes 12 hours?

 

[SDP79]

Hi, there is a difference between Go and Go faster. Go is 4 hour go faster is 3,4 or 5 staring at different times.
If you get a smart EVSE like the Ohme from Octopus Energy then you set that for you cheap tariff.
To balance charge just leave it connected the car takes care of the charging dropping the power down from 7.5kw to about 300-500w.
How do know it takes 12 hours?

Thank you for this. I was not aware of the other Octopus tariffs. I am unable to make any time settings on my charger which is from ChargedEV. The car starts to charge during the cheap rate that I have set on the charger but it keeps on going till 100% regardless of whether it is balancing or otherwise. I am unable to limit the charge to just the cheap tariff.
As I say I always have to charge to 100% unless I wait up till 4.30am and switch it off!.
When below 30% and I plug in to charge, sometimes it charges at around 6.8 kwh for the low rate then charges at around 1kwh until it is at 100% - all in all takes around 11 -12 hours.
It is very inconvenient for the car to go in to a balance charge for an extended period when I have to use the car in the morning. I simply have to turn off and use the car! I was hoping somewhere that you can actually set the car to balance charge - this would make sense of the suggestion that this could be done once a month. But this does not seem to be the case - and it seems to be some what random - I have never had a warning in the car before charging that a balance charge would be performed.
Thanks for your help.

 

[Lguk]

If your charger has a start time, it almost certainly has the ability to have a stop time.
Which point do you have?

The idea is you start/stop for your cheap electricity window then once a month manually charge to 100% and leave it on to balance.

 

[SDP79]

If your charger has a start time, it almost certainly has the ability to have a stop time.
Which point do you have?

The idea is you start/stop for your cheap electricity window then once a month manually charge to 100% and leave it on to balance.

Hello - Yes I have researched this but it is not the case of putting a start time in the machine which is - ChargedEV

ChargedEV

The UK's smartest EV charger, the Smart Pro - available at just £649.

www.chargedev.co.uk

You can set a duel tariff and it starts to charge during this period but you cannot limit the charging to this time period. I have consulted with the manufacturers and they confirm this. There are some vehicles such as my previous Nissan Leaf that you could set charge periods on the car. The current MG5 is as far as I know without this function.
Thanks for your interest

 

[AnonymouseDriva]

1) It is 4hrs a night for me -0030 to 0430 - is this just a typo?
2) How do you manage to limit the charging to this amount of time? As far as I am aware there is no facility with the MG5 to set timing of charge. Do you set the charger to turn off after 3 or 4 hours?
3) There seems to be no system to regularly do a balance charge - ie you cannot set the car to perform this task so how do you have a balance schedule if it is totally random? There seems to be several comments on here about setting a balance charge - can you please advise as to how this is done or am I just reading this incorrectly?

Hi
1) As above, I'm on go faster. I chose to take 3 hours at a slightly lower rate. When I signed up it was 3h at 4.5p, 4h at 5p or 5h at 5.5p per kwh.
2) I have a hypervolt and can schedule the charge on that. Before that I used the granny charger and an Ikea TRADFRI smart plug (rated high enough to take the load).
3) It just does it every time the car hits 100% charge. As I only leave it on long enough to charge to 100% if I know I'm on a long trip, that's how I 'schedule' it.

 

[Lguk]

Hello - Yes I have researched this but it is not the case of putting a start time in the machine which is - ChargedEV

ChargedEV

The UK's smartest EV charger, the Smart Pro - available at just £649.

www.chargedev.co.uk

You can set a duel tariff and it starts to charge during this period but you cannot limit the charging to this time period. I have consulted with the manufacturers and they confirm this. There are some vehicles such as my previous Nissan Leaf that you could set charge periods on the car. The current MG5 is as far as I know without this function.
Thanks for your interest

They supply multiple different brands chargers. Including one that claims to be the 'smartest ever'. If you know which model you have and which app it uses, others may have experience or workaround that can help you. Always charging to 100% and starting a balance isn't really ideal.

You're correct then mg5 doesn't have an inbuilt app or schedule, you will be relying on the charger side being smart.