What's the effect on battery life of regularly charging to 100%

[tsedge]

I think I was quite clear in my post, which was intended to be a single, one-off public information announcement.

Ok, I will add similar announcements where appropriate to SR / SE threads.

 

[Rolfe]

This is getting ridiculous. There's a genuine problem of SR owners not understanding that their battery chemistry is different and that they shouldn't be following the ubiquitous instructions about charging that are all over the place but apply only to the NMC batteries. The title of this thread said nothing about it applying only to the LR batteries.

When you find that owners of NMC batteries are being confused because everyone is talking about LFP batteries as if they were the only sort that existed, you might have a point.

We already have Trophy owners swarming all over the SE threads telling us that their cars don't behave like this. We don't need any more.

 

[tsedge]

This thread was proceeding fine before you decided to add your announcement.

Nobody is swarming anywhere and you seem to have a real chip on your shoulder about Trophy owners. I am not hearing other people make the same complaint.

There is confusion all over the place because of the lack of communication from MG and it is easy for people to get things mixed up. It is hard enough to keep track as a regular, let alone for new or casual reader.

I am simply trying to figure out the best way to solve this - you've suggested and started public service announcements and I've followed. If that isn't the approach then we need to do something else like clearly mark ALL thread titles and/or have separate SR/LR and SE/Trophy sub forums.

Anyway, I can see that we aren't getting anywhere - I will leave this alone now for other people's sake.

 

[Ian Key]

 

[Tig170]

Also have a look at :



4mins in : NMC 100% DoD you'll get 300 cycles, and 600 LFP

Ref: BU-808: How to Prolong Lithium-based Batteries

 

[Barrie]

Just returned my 2 year old Mk1 ZS. I charged it to 100% every time via a granny charger at 2.2kw and it never got charged away from home. Sometimes sat for days at 100% without being used as I needed it at a moment's notice for possible long journeys for my business. Battery was degraded by 0.8% so that would be a 4% loss in 10 years. Don't worry about it.

 

[Rolfe]

Forgive my ignorance, but I presume that's an NMC battery? That is indeed very reassuring indeed.

 

[Barrie]

It was a MK1 ZS so I presume it was NMC ? I really do think there is too much concern around battery charging. If I can't charge it and use 100% what's the point ? The BMS will take care of it. I now have an MG Marvel with 70kw battery that I bought outright and intend to use it just the same. If I live 10 years I will report back

 

[Rolfe]

I thought so, but I haven't been at this long! If an NMC has so little degradation after two years of that, it very much backs up what Euan McTurk is saying in that video about not worrying about it unless you're leaving the car for ages, or leaving it for a week or two more than occasionally.

I get it that people want to do their best by their battery and follow the manufacturer's instructions, but once it gets to be a chore I think it's a good thing to realise that it isn't that critical.

 

[firstMGEV]

My wife has a 145 mile round journey for her three days a week commute in an MG Trophy LR (61kw battery). We have been charging to 80% in line with recommendations to preserve battery life. But now that winter is coming she is experiencing range anxiety. I say don't worry but that is easy for me to say as I am not experiencing what she is. Today, for example, she was limiting her speed to around 50mph on roads that are 70mph to ensure she had a decent margin of charge to get her home. When she got home she had 12% left (i.e. she was achieving 3.5 miles per kw and had a decent margin to spare) which would be fine if she wasn't having to limit her speed. Limiting her speed in this way is not at all ideal as it prolongs an already long working day so I think she may have to revert to 100% battery charging. Does anyone have any information or evidence on the impact on battery life of 100% charging?

p.s. she is driving in energy saving mode, max regen etc.

I’m a taxi driver and I’ve been charging up to 100% 6 days a week minus some days off once in a while for a year now and my battery life was at 100% on my 30k service so don’t worry about it!

 

[ari197]

I thought with LFP batterys it doesn't affect them. I could be wrong tho. I don't have home charging facility so I only use public chargers and so far I've not had the battery below 30% and charge it to 97% ( for some reason it never gets to 100% ) I've only got the car for 3 years so it's not so much of a issue with me.

I found an article once..
1. LFP battery is more stable and thus will have more charge cycle
2. LFP battery has a more stable voltage curve.. which add difficulty for the BMS to know how much battery left..

That's why Tesla and other manufacturers suggested to regularly LFP batt to 100%, so that the BMS is always on track, knowing that it won't damage the batt as much..

But the general caution about not leaving your batt at 100% SoC too long still applies

 

[Mennox]

If that isn't the approach then we need to do something else like clearly mark ALL thread titles and/or have separate SR/LR and SE/Trophy sub forums.

Why not just create a new thread with an appropriate title which explains the differences between battery types and sticky it so its easily accessible for those that need to reference it?

 

[Scoozy]

I charge mine every time to 100% on a wall AC charger @ 7Kw but drive every day +/- 100km so the car never stays a long time @ 100% battery level.

 

[Jto]

Thanks for that reply. I think she is doing all those things but I will doublecheck re point about eco being set on AC. For the work commutes we will charge to 100% and see what the margin of safety is in lower temperatures. If it seems safe to do so, is there any merit in setting the max charge to 90% instead of 100% or is there some 'magic' about 80%?

The weather has not got that cold until today so it may be a good idea to show her how to charge the car at a charge station for top up. You may find that a top may have to been done on a fast charger, you be putting in 20 to 30 miles which will not cost too much but she will not get stuck.

 

[Corindikev]

The problem with the battery university data is that the tests are done on mobile phone pouch batteries with no battery monitoring or conditioning systems. Also if you are only charging & discharging 10% of the battery's capacity then the number of cycles over time increases massively.

I prefer to take the advice of Euan McTurk as he explains the issue with regard to EV batteries not any single cell Li-ion battery that has no temperature management or any other conditioning software at all. His advice, don't micro charge (like that bloke was doing) and don't leave the NMC battery at 100% for months at a time.

 

[Nobbyplopps]

Depends if you brought the car or if it’s lease

 

[brianharries]

My wife has a 145 mile round journey for her three days a week commute in an MG Trophy LR (61kw battery). We have been charging to 80% in line with recommendations to preserve battery life. But now that winter is coming she is experiencing range anxiety. I say don't worry but that is easy for me to say as I am not experiencing what she is. Today, for example, she was limiting her speed to around 50mph on roads that are 70mph to ensure she had a decent margin of charge to get her home. When she got home she had 12% left (i.e. she was achieving 3.5 miles per kw and had a decent margin to spare) which would be fine if she wasn't having to limit her speed. Limiting her speed in this way is not at all ideal as it prolongs an already long working day so I think she may have to revert to 100% battery charging. Does anyone have any information or evidence on the impact on battery life of 100% charging?

p.s. she is driving in energy saving mode, max regen etc.

The Standard Range model uses a 51 kWh LFP battery, and the Long Range has a 64 kWh NMC battery. My current understanding is that the LFP battery (the 51kWh) likes to be charged to 100% and depleted regularly, but the NMC battery (long range) thrives on the 20% - 80% guideline.

 

[Rolfe]

The Standard Range model uses a 51 kWh LFP battery, and the Long Range has a 64 kWh NMC battery. My current understanding is that the LFP battery (the 51kWh) likes to be charged to 100% and depleted regularly, but the NMC battery (long range) thrives on the 20% - 80% guideline.

That's right. I don't know about "depleted regularly", as to how regularly is regularly. The handbook says to go down below 10% then charge up all the way on an AC charger every three to six months. I last did that in September sometime.

Now that the weather is cold, which affects the range, I tend to charge up again when I get below 70%. Of course now and again I'm below 40% when I get home so it's probably all fine.

 

[Harlequin]

Charging to 100% is fine whenever you need it, it is recommended at least once a month to balance the battery.

The thing that ages a battery is time spent at 100% (or close to it), that's what you want to minimise - so don't leave it with a high state of charge. Rapid charging also has a wearing effect.

However, batteries last so well that it won't really affect you unless you plan to keep the car for 10 years and go well around the clock. All the models should be good for 200,000 miles with a decent battery life left.

Also make sure she has:

• ECO mode on
• Energy saving on in ECO mode
• ECO set on AC
• AC Temperature not too high and low fan speed
• Intelligent battery heating set to OFF

145 miles should be no trouble at all for a LR, minimum I get even driving hard in sport mode is around 180 miles.

50mph should give you around 4m/kWh or more, suggesting that something is not set right.

Finally, there's nothing wrong with getting home with 12%.

Sorry to intrude on this thread, but I spotted a couple of things on this reply, that I'd like some clarification on, please

Also make sure she has:

• ECO mode on - I know how to do this.
• Energy saving on in ECO mode - Please explain, thanks.
• ECO set on AC - I know about the Eco drive mode, but not ECO on on the AC - please explain, thanks?
• AC Temperature not too high and low fan speed - I know what this is
• Intelligent battery heating set to OFF - Never heard of this, please explain, thanks?

Thanks in advance

 

[Harlequin]

Sorry to intrude on this thread, but I spotted a couple of things on this reply, that I'd like some clarification on, please

Also make sure she has:

• ECO mode on - I know how to do this.
• Energy saving on in ECO mode - Please explain, thanks.
• ECO set on AC - I know about the Eco drive mode, but not ECO on on the AC - please explain, thanks?
• AC Temperature not too high and low fan speed - I know what this is
• Intelligent battery heating set to OFF - Never heard of this, please explain, thanks?

Thanks in advance