Charging 10%-100% every 3-6 months

Jeroen said:
Well doing the 7-100% charge last night did help recalibrate the GOM and BMS.

Drove to work today and have 97% left, where 2 weeks ago after charging from 50-ish to 100 it was at 88%.

So it did actually help to calibrate the BMS.
Click to expand...
I think this should answer the questions above around what this thread is about.
 
fnegroni said:
I think this should answer the questions above around what this thread is about.
Click to expand...

No it doesn’t and it’s not what the thread is about, my original question was about charging from 10-100% and if that could be split over 2 charges due to off peak energy rates.

We have then since found out there’s a lot of misinformation including the manual & directly from MG themselves.

We need clarity directly from MG who understand the 2 different battery types
 
pecker said:
No it doesn’t and it’s not what the thread is about, my original question was about charging from 10-100% and if that could be split over 2 charges due to off peak energy rates.

We have then since found out there’s a lot of miss information including the manual & directly from MG themselves.

We need clarity directly from MG who understand the 2 different battery types
Click to expand...
It doesn’t answer your specific question. It does however answer some questions that were raised around the issue this thread is about, including whether it’s really necessary.
The thread went in many directions.

for what it’s worth, to add my tuppence to it, we have established that it’s important for the BMS to see the full range of charge from below 10% to 100% (and above, ie equalisation)
you could start by making sure you do charge from below 10% once every 3 months.
If you want to, you could do that as part of a charge to 100% but split over two or three sessions.
If you though stumble upon issues that this is meant to prevent, you could try to do a continuous charge from below 10% to 100% and see if that resolves any issues you might have encountered despite the split charge.

I agree, an answer from mg would be welcome.
But was that the question asked directly to customer support by @Ian Key earlier?
 
fnegroni said:
It doesn’t answer your specific question. It does however answer some questions that were raised around the issue this thread is about, including whether it’s really necessary.
The thread went in many directions.

for what it’s worth, to add my tuppence to it, we have established that it’s important for the BMS to see the full range of charge from below 10% to 100% (and above, ie equalisation)
you could start by making sure you do charge from below 10% once every 3 months.
If you want to, you could do that as part of a charge to 100% but split over two or three sessions.
If you though stumble upon issues that this is meant to prevent, you could try to do a continuous charge from below 10% to 100% and see if that resolves any issues you might have encountered despite the split charge.

I agree, an answer from mg would be welcome.
But was that the question asked directly to customer support by @Ian Key earlier?
Click to expand...

The problem is this is just guess work as MG themselves have contradicted their own manual.

We really need clarification from MG
 
fnegroni said:
It doesn’t answer your specific question. It does however answer some questions that were raised around the issue this thread is about, including whether it’s really necessary.
The thread went in many directions.

for what it’s worth, to add my tuppence to it, we have established that it’s important for the BMS to see the full range of charge from below 10% to 100% (and above, ie equalisation)
you could start by making sure you do charge from below 10% once every 3 months.
If you want to, you could do that as part of a charge to 100% but split over two or three sessions.
If you though stumble upon issues that this is meant to prevent, you could try to do a continuous charge from below 10% to 100% and see if that resolves any issues you might have encountered despite the split charge.

I agree, an answer from mg would be welcome.
But was that the question asked directly to customer support by @Ian Key earlier?
Click to expand...
I repeat, I have had the car over a year and never gone down to 10% and everything is fine.

I think we have established that these things are supposed to ensure the battery lasts a long time and is in tip-top health.

But we haven't established either the proper protocol (as @pecker says) or whether it really matters.

Using these as techniques to help when there is a problem isn't the same as them being regularly needed.
 
tsedge said:
I am debating whether to continue to bother with any of this guidance or just charge the car as I please. I have my doubts I will notice the difference.
Click to expand...

I suspect you'd be just fine, actually. And if you were finding that the GOM was being too unreliable for your tastes, you'd have the option to balance, or do the long balancing charge, then.
 
tsedge said:
I think we have established that these things are supposed to ensure the battery lasts a long time and is in tip-top health.

But we haven't established either the proper protocol (as @pecker says) or whether it really matters.

Using these as techniques to help when there is a problem isn't the same as them being regularly needed.
Click to expand...
I understand you don’t have any issues and I’m glad you don’t, maybe I would not either was I not following the advice from the manual and in the way I do. But, I somewhat disagree on those points you mention:

1) 10 to 100 charge has more to do with the BMS recalibration which is needed to ensure You get as accurate a state of charge as possible and you get all the range you paid for.

2) we don’t know ‘some’ detail of the protocol, but we know it matters. And a member just posted reporting how it fixed their dodgy charge percentage bar.

3) If the problems appear as a result of not doing these things regularly, then doing them regularly is the fix: prevent rather than cure.

Hey, my car has no charging state issues either. I could stop doing that charge from below 10% for a little over 6 months and see what happens. But I don’t need to worry because I am forced to charge from 5% at times without choice anyway and because I have access to free charging at the moment.

I agree we need more clarity from MG. Especially because of the NMC vs LFP general battery chemistry recommendations found on the web.

But to me it makes sense to err on the side of caution and do this once every three to six months in a single charging session rather than split it across multiple charging sessions.
 
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I want to be able to rely on the GOM and the SoC indicator. I don't drive the car low very often - using a granny charger means I usually keep it topped up for the sake of speed - but I want to know it'll be right if I do go low.

I have driven under 10% probably half a dozen times in total. Each time the car was spot on with its range estimates. I've also learned to be able to think ahead and estimate how my intended usage will differ from the car's estimate, which is based on how I've been driving over the previous 50 miles or so. When I do go for longer distances, as I intend to in the summer, I want to be able to continue to rely on these estimates. I do not want the car suddenly to drop from 20% to 8% when I'm on the motorway, as I've heard has happened to others. So I'll go on following the recommendations.

When I've been away overnights I have always managed to find a type 2 charger to sit on at some point in my visit, so that the pack was balanced before the return journey. This may not really be essential, but I see it as a reasonable precaution.
 
fnegroni said:
I understand you don’t have any issues and I’m glad you don’t, maybe I would not either was I not following the advice from the manual and in the way I do. But, I somewhat disagree on those points you mention:

1) 10 to 100 charge has more to do with the BMS recalibration which is needed to ensure You get as accurate a state of charge as possible and you get all the range you paid for.

2) we don’t know ‘some’ detail of the protocol, but we know it matters. And a member just posted reporting how it fixed their dodgy charge percentage bar.

3) If the problems appear as a result of not doing these things regularly, then doing them regularly is the fix: prevent rather than cure.

Hey, my car has no charging state issues either. I could stop doing that charge from below 10% for a little over 6 months and see what happens. But I don’t need to worry because I am forced to charge from 5% at times without choice anyway and because I have access to free charging at the moment.

I agree we need more clarity from MG. Especially because of the NMC vs LFP general battery chemistry recommendations found on the web.

But to me it makes sense to err on the side of caution and do this once every three to six months in a single charging session rather than split it across multiple charging sessions.
Click to expand...

Can I get ask where you got your information from regarding point 1 please ?

Cheers pecker

Thanks
 
fnegroni said:
I understand you don’t have any issues and I’m glad you don’t, maybe I would not either was I not following the advice from the manual and in the way I do. But, I somewhat disagree on those points you mention:

1) 10 to 100 charge has more to do with the BMS recalibration which is needed to ensure You get as accurate a state of charge as possible and you get all the range you paid for.

2) we don’t know ‘some’ detail of the protocol, but we know it matters. And a member just posted reporting how it fixed their dodgy charge percentage bar.

3) If the problems appear as a result of not doing these things regularly, then doing them regularly is the fix: prevent rather than cure.

Hey, my car has no charging state issues either. I could stop doing that charge from below 10% for a little over 6 months and see what happens. But I don’t need to worry because I am forced to charge from 5% at times without choice anyway and because I have access to free charging at the moment.

I agree we need more clarity from MG. Especially because of the NMC vs LFP general battery chemistry recommendations found on the web.

But to me it makes sense to err on the side of caution and do this once every three to six months in a single charging session rather than split it across multiple charging sessions.
Click to expand...
Fine.

We need people to experiment with not following the rules too, that way we can tell how much they matter.

So I am going to ignore them and see what happens.
 
pecker said:
Can I get ask where you got your information from regarding point 1 please ?

Cheers pecker

Thanks
Click to expand...
you are right.

Admittedly it’s an educated guess.
I can’t find any evidence that discharging to less than 10% and then back to full 100% improves the actual physical properties of the battery, more like the opposite. Discharging and charging batteries by itself only degrades a battery, and the bigger the difference in SoC the worse.
If you did this every day, it would shorten the life of your battery severely.

So I doubt the recommendation is made to improve the battery health.

Reading about BMS systems, I’m inclined to believe it’s to ensure the BMS is correctly calibrated.

Calibrating the Battery Management System - Help Center - Tessie

Your Tesla's Battery Management System (BMS) calculates your range, battery level and capacity. Over time, these calculations may become inaccurate because: The
help.tessie.com help.tessie.com

tesla-info.com

Tesla battery management system (BMS) calibration

Tesla battery management system (BMS) calibration instructions
tesla-info.com tesla-info.com
 
Last edited:
siteguru said:
That's already been posted in this thread - post #48.
Click to expand...

That’s why I’m concerned, if its from the manual it maybe wrong information as it doesn’t state which battery type it’s making that recommendation for.

We just need to be careful posting opinions as fact because MG don’t appear to be able to get it right either.

I’m totally confused by all this and I’m not going to bother worrying anymore, will just charge to 80% unless in need 100

Thanks everyone who tried to answer my original question, however I feel we are going off on a tangent now.
 
pecker said:
That’s why I’m concerned, if its from the manual it maybe wrong information as it doesn’t state which battery type it’s making that recommendation for.

We just need to be careful posting opinions as fact because MG don’t appear to be able to get it right either.

I’m totally confused by all this and I’m not going to bother worrying anymore, will just charge to 80% unless in need 100

Thanks everyone who tried to answer my original question, however I feel we are going off on a tangent now.
Click to expand...
tesla-info.com

Tesla battery management system (BMS) calibration

Tesla battery management system (BMS) calibration instructions
tesla-info.com tesla-info.com

Calibrating the Battery Management System - Help Center - Tessie

Your Tesla's Battery Management System (BMS) calculates your range, battery level and capacity. Over time, these calculations may become inaccurate because: The
help.tessie.com help.tessie.com

I hope you find the answer but in the meanwhile the link I posted earlier (and here again) might help you making your mind up as to whether to charge from below 10 to 100 and whether to do it in one go is necessary or not.
 
I was explaining to a friend about limiting charging % to prolong battery life, shortly after my Android updated itself to give me the option to limit charge to 85%. She also has an Android. She can't find any similar facility on her phone.

When she was in the shop with the phone the other day she mentioned this to the assistant, who said, no don't do that, you'll kill the battery. You should always discharge right to empty then charge all the way to 100%. I'm pretty sure that's wrong whatever type of battery that phone has!

It's odd that the option to limit the charge isn't on her phone, a bit like it's not on the MG app for the SE SR. It makes me wonder if her phone has an LFP battery, but I have no idea how to find out. But surely draining to zero then charging to 100% is an outdated recommendation relating to memory effects which are no longer an issue, and is not the best way to manage any modern battery.
 
/off-topic ... it depends on a) what phone she has and b) what version of Android it is running. My Moto G8 Plus phone running A10 doesn't have that option.
 
fnegroni said:
But was that the question asked directly to customer support by @Ian Key earlier?
Click to expand...
Just for clarification here is a copy of my original email and the reply from MG.

I have an MG4 Trophy and it is recommended to do a balance charge from 10% to 100% every 3 months to look after the health of the battery.

My question is, has this charge got to be completed in one session or can it be split over two nights?

The reason I ask is I don't get enough hours on the cheaper rate of my EV tariff to go from 10% to 100%

And MG replied:

Thank you for contacting MG Motor UK Ltd.

The recommendation from MG Motor UK Ltd. is to charge to 100% and carry out an equalisation charge thereafter, as often as you can manage. It would be better to complete this action weekly or bi-weekly rather that every 3 months.

I apologise, but I do not know where the 3 months comes from, and this is an essential part of keeping the individual cells balanced and healthy.

To which I replied:

Thank you for getting back to me.

The 3 months charge comes from page 295 of the owner's manual which states:

"When using the vehicle on a daily basis. it is recommended to fully charge at least once a week, which is conductive to the health maintenance of the high-voltage battery pack; every 3 months to half a year, a low power (less than 10% or 1 grid) full charged is performed.

I am waiting for a reply.
 
I have read right now the higher % of EV owners ( not just MG ) can charge at home

Obviously though there are people who can only rely on public chargers & as time goes on this number will increase. I’ve posted myself I have a neighbour who has an MG ZS EV who hasn’t the option of a home charger & has only used public fast chargers & the car is just under 7000 miles & he’s had no issues

Now I’m not saying people shouldn’t follow the advice from the car manufacturers, balancing, slow charging etc when possible but for a lot of people this just won’t be possible & as mentioned in this thread, I bet a lot of people won’t follow the guidelines let’s say to the letter. They just want to charge the car & go

So I’d hope even though it’s not ideal but the car/batteries should be able to cope for all kinds of running/usage?
 
fnegroni said:
you are right.

Admittedly it’s an educated guess.
I can’t find any evidence that discharging to less than 10% and then back to full 100% improves the actual physical properties of the battery, more like the opposite. Discharging and charging batteries by itself only degrades a battery, and the bigger the difference in SoC the worse.
If you did this every day, it would shorten the life of your battery severely.

So I doubt the recommendation is made to improve the battery health.

Reading about BMS systems, I’m inclined to believe it’s to ensure the BMS is correctly calibrated.

Calibrating the Battery Management System - Help Center - Tessie

Your Tesla's Battery Management System (BMS) calculates your range, battery level and capacity. Over time, these calculations may become inaccurate because: The
help.tessie.com help.tessie.com

tesla-info.com

Tesla battery management system (BMS) calibration

Tesla battery management system (BMS) calibration instructions
tesla-info.com tesla-info.com
Click to expand...
The Tesla guide explains it very well and I'm sure the same theory applies to our MG's, its not causing any damage to the cells if you don't do this 10-100%, its just so the BMS will report the range more accurately, which is useful as previous posts say the range suddenly drops from 20-8%, not good if nearest charger is 30miles away and if calibrated more precisely this wouldn't happen.
 
Screenshot_20240228_094812_Messenger.jpg


Screenshot_20240228_094840_Messenger.jpg


I'm totally confused, from mg Ireland a few weeks ago is to fully charge once a week,reply last August is to fully charge once a month, trophy owner
 

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