Charging 10%-100% every 3-6 months

Kevin Smith said:
I agree. The manual just describes type 1 &2 batteries and it took some digging to find out the 51 kWh battery is LFP. These tolerate deeper cycles better and like charging fully. It would be so easy to put a battery card into each car with details of management recommendations or just a QR code sticker in the charging hatch leading to details online!
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I like the QR code idea.

Knowing exactly which components and features a car has, has always been a problem for me. The manual normally describes all components and features that have ever been on all variants of a particular model for the last 10 years.

If a QR code on the infotainment version number page took you to a web page which listed everything in your car, it would be a great help especially as the model matures.
 
My Trophy dropped to 20% yesterday and the car voice told me the the battery level was low and that I should charge as soon as possible. I did not and this morning it was at 19% and again I received the warning message on startup. Seems to make a mockery of 10%-100% charging if I have to ignore the message.
 
Martinonline said:
My Trophy dropped to 20% yesterday and the car voice told me the the battery level was low and that I should charge as soon as possible. I did not and this morning it was at 19% and again I received the warning message on startup. Seems to make a mockery of 10%-100% charging if I have to ignore the message.
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I don't believe anyone has said you should ignore the message, the grey area is the manual states we need to run the car down to 10% and charge up to 100% once every 3-6 months.

What's not clear if this applies to both battery types.
 
Does anyone have a point of contact at MG where we can find out for definite, I don't fancy our chances calling customer services lol
 
I think the SE’s R33 is the only release where they got the battery charge bar and warning level consistent. Prior SE versions and R46 still have bizarre warnings/colours.

The 10 to 100 charge is to prevent sudden drops in charge level. And I guess only MG knows what is best for their BMS.
 
Just drove a few extra kilometers to get the SOC below 10%, managed to get it down to 7% for the first time before getting too anxious.

Now charging the car to 100% and I’m curious whether the charge indicator will drop from 100% to 80-something within just a few kilometers (less then 15 km) as it did the last 3 times (could be more) I charged to 100%.

Normally I charge to 80% every other day and rarely go below 40%. I only charge to 100% before doing a long journey. The charge indicator drops significantly slower when charged to 80%.

I am on R46 and the indicator was still green at 7%. Did receive the warning message at 12%.
 
On my SE the indicator went amber at 12%, then when I had to put in a bit more juice due to a change of plan, at 10% the second time. I'm still on R13. I don't know what to make of it.
 
As promised here is the reply from MG Customer Services:

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.

I have replied quoting the text and the page number of the owner's manual. I make no further comment.
 
Thanks for posting the reply from MG Ian.

However to me that advice contradicts the advice not to charge the NMC batteries that our Trophy LR have to 100% too often.

The advice seems more appropriate for the LFP batteries.

It might explain why the batteries drain so quickly from 100 to 80 percent as I do my balancing at 80% at least 2 to 3 times a week.

Still confused 🫤
 
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Ian Key said:
As promised here is the reply from MG Customer Services:

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.

I have replied quoting the text and the page number of the owner's manual. I make no further comment.
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It is the right thing to do to press MG to make the advice clear across battery types. Thank you for pursuing this.
 
Jeroen said:
Thanks for posting the reply from MG Ian.

However to me that advice contradicts the advice not to charge the NMC batteries that our Trophy LR have to 100% to often.

The advice seems more appropriate for the LFP batteries.

It might explain why the batteries drain so quickly from 100 to 80 percent as I do my balancing at 80% at least 2 to 3 times a week.

Still confused 🫤
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Yes @Jeroen the car does balance at 80% (or any other % you set) but if the top 20% of the cells won't be being balanced. Keep charging as you have been doing but once a month using an AC charge point charge to 100% and leave the car connected until it stops drawing any current.

I think there are two different things going on here.

The 100% balance charge is for the health of the battery by making sure all the cells are performing equally and stop a weak cell underperforming dragging the healthy cells down to its performance.

The under 10% to 100% charge is to calibrate the BMS, GOM etc.
 
Ian Key said:
I think there are two different things going on here.

The 100% balance charge is for the health of the battery by making sure all the cells are performing equally and stop a weak cell underperforming dragging the healthy cells down to its performance.

The under 10% to 100% charge is to calibrate the BMS, GOM etc.
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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.
 
Jeroen said:
I do my balancing at 80% at least 2 to 3 times a week.
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? Balancing is where you leave the "charger" connected after the car reaches 100%. [ Edit: Oops! I was thinking Mark 1 ZS EV; see next 2 posts. ]

I think you're saying that you recharge to 80% at least 2-3 times per week. That's fine, but it's not what we're calling "balancing".

The BMS may or may not be adjusting the charge of cells when sitting at 80%, but the part that requires slightly extra attention from us is what happens when you leave the "charger" connected after the car says that it reaches 100%. This is what we call "balancing".
 
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Coulomb said:
? Balancing is where you leave the "charger" connected after the car reaches 100%.

I think you're saying that you recharge to 80% at least 2-3 times per week. That's fine, but it's not what we're calling "balancing".

The BMS may or may not be adjusting the charge of cells when sitting at 80%, but the part that requires slightly extra attention from us is what happens when you leave the "charger" connected after the car says that it reaches 100%. This is what we call "balancing".
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Is it not the case that if you set the charge limit to say 80%, the BMS will do an equalisation of all cells to80% by drawing a little current over say half an hour or so? I think that’s what people claim to have seen: the charger is connected to the car, the battery state of charge reaches 80%, and with the charger still connected, the car itself shows ‘balance charge’ on the display and draws a little current to perform the equalisation.

If the above is true, the problem is that the BMS’s idea of what 80% is differs slightly and over time might be much less.

Balancing or not balancing.

And explains how charging from below 10% to 100% helps the BMS recalibrate itself.
 
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fnegroni said:
is it not the case that if you set the charge limit to say 80%, the BMS will do an equalisation of all cells to80% by drawing a little current over say half an hour or so?
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Ah, my bad!

Mine is a Mark 1 ZS, and it doesn't have the ability to set an SoC limit. It looks like these models will be doing such balances at 80% or wherever you set the limit.

It's an interesting question as to whether this obviates the need for occasional 100% charging. I imagine that the "best" balancing will happen at 100% SoC, but a balance at say 80% twice a week might end up being better than one balance to 100% every month.
 
tsedge said:
No wonder people are confused. The messaging on this is awful.

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.
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Totally agree. 🙂👍
 
fnegroni said:
Is it not the case that if you set the charge limit to say 80%, the BMS will do an equalisation of all cells to80% by drawing a little current over say half an hour or so? I think that’s what people claim to have seen: the charger is connected to the car, the battery state of charge reaches 80%, and with the charger still connected, the car itself shows ‘balance charge’ on the display and draws a little current to perform the equalisation.

If the above is true, the problem is that the BMS’s idea of what 80% is differs slightly and over time might be much less.

Balancing or not balancing.

And explains how charging from below 10% to 100% helps the BMS recalibrate itself.
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That's all good if you can set your SoC to 80% & get a balance, but my LR still won't stop at 80%, so have to go to 100% to achieve a balance about once a week. Due back in the dealership beginning on April for 1st service and hopefully rectify problem.
 
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tsedge said:
No wonder people are confused. The messaging on this is awful.

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.
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Completely agree, I will continue to charge to 80% unless I need the extra range when will charge to 100% and let it balance.

However, there must be someone who can confirm at MG, maybe @Miles Roberts CG can help

Cheers
 

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