Battery chemistry reason enough to go for the SE SR?

[zAndy1]

So I've been giving this some thought and ignoring for a moment the extra features the trophy has there's a good argument for getting the SE SR purely due to the battery chemistry. As you probably know the SE SR can be safely charged to 100% whereas the LR battery should only be charged to 80% which means effectively the ranges are the same if you want to look after the battery. Also the NMC battery is apparently far more prone to catching fire and when it does it does so in a way that severely restricts your chances of living to tell the tale. Check out this video about this subject.


I'm actually considering changing my Trophy lease order to an SE SR , the SE SR is £70pm less for a start and the range will be fine for our needs and if it's safer as well that's a bonus. Thoughts?

 

[Rolfe]

Hmm. As an SR owner I've given this a bit of thought, and agree with you to some extent. However I think the problems with NMC battery management can be over-stated.

Most EVs have NMC batteries and they are not bursting into flames all over the place. There certainly hasn't been a safety recall on them in which owners were advised to park their cars away from their houses until the remedial work was done, as happened to 91,000 ICE cars recently! (When I was still at school I saw an ICE car burst into flames right in front of me on the road - it was about three cars ahead of ours in slow-moving traffic. The occupants escaped, but this was before the days of compulsory seat belts, so I wonder.)

You do have the extra range, whenever you need it. The advice is not to let the battery sit at over 80% for days on end, and not to charge it beyond 80% unless you need the range. Obviously, if you do need the range, go for it - you'll soon drive it down below 80%.

The main difference day to day is that the NMC likes being cycled up and down between 20% and 80%, and only needs to be balanced at 100% once a month. The SR doesn't like that, and prefers to be taken to 100% and allowed to balance whenever you charge - unless you're out on the road on a long journey, that is. You can even run the SR on short journeys and come home and bring it back to 100% every time, if you want to. Don't do that with the NMC, you'll kill the battery.

This video is a good rundown on the two types of battery, and might calm your fears about the NMC if that's the one you decide to go for.



These differences in behaviour make the NMC more suitable, in my opinion, for people who can't charge at home. Just graze as you can, use AC or DC chargers as is convenient to you, and only take the trouble to let the car sit and balance on a DC charger or a granny lead once a month. I don't think the SR would take so kindly to that. (The main issue seems to be that the car starts reporting range and % charge remaining incorrectly, and I think this may be what was behind two or three incidents on YouTube where drivers of LFP-battery cars ran their batteries flat because the reported range dropped from 15 miles to about 4 miles very suddenly.)

But for charging at home, the SR is brilliant. I just drive mine until I reach the point where I think I'd rather not leave it with so little range in case of eventualities, or I have a longer trip the next day, and then charge to 100%. No worrying about stopping at 80%.

There is another advantage the NMC has though. As well as having a longer range, it charges faster on a DC charger - the MG LR battery has a max of 140 Kw as opposed to the SR's max of about 88 Kw. So if you do use the SR for a long trip, then you have to stop more often and these stops will be a bit longer.

For me, I do long trips very infrequently, and wasn't fussed about an extra stop or a bit longer in the café when I did. 99% of the time I am never going to drive beyond the practical range of the car, and I really couldn't justify £2,500 extra for the LR battery.

Also, the LFP lets you be smug and superior because it doesn't contain cobalt.

I think the SE SR is great value for money, but the NMC battery is a good product, it's serving many people very well indeed, and if you do want the extra bells and whistles on the Trophy (and can afford them), then I don't think you should really let the battery put you off too much.

 

[zAndy1]

Hmm. As an SR owner I've given this a bit of thought, and agree with you to some extent. However I think the problems with NMC battery management can be over-stated.

Most EVs have NMC batteries and they are not bursting into flames all over the place. There certainly hasn't been a safety recall on them in which owners were advised to park their cars away from their houses until the remedial work was done, as happened to 91,000 ICE cars recently! (When I was still at school I saw an ICE car burst into flames right in front of me on the road - it was about three cars ahead of ours in slow-moving traffic. The occupants escaped, but this was before the days of compulsory seat belts, so I wonder.)

You do have the extra range, whenever you need it. The advice is not to let the battery sit at over 80% for days on end, and not to charge it beyond 80% unless you need the range. Obviously, if you do need the range, go for it - you'll soon drive it down below 80%.

The main difference day to day is that the NMC likes being cycled up and down between 20% and 80%, and only needs to be balanced at 100% once a month. The SR doesn't like that, and prefers to be taken to 100% and allowed to balance whenever you charge - unless you're out on the road on a long journey, that is. You can even run the SR on short journeys and come home and bring it back to 100% every time, if you want to. Don't do that with the NMC, you'll kill the battery.

This video is a good rundown on the two types of battery, and might calm your fears about the NMC if that's the one you decide to go for.



These differences in behaviour make the NMC more suitable, in my opinion, for people who can't charge at home. Just graze as you can, use AC or DC chargers as is convenient to you, and only take the trouble to let the car sit and balance on a DC charger or a granny lead once a month. I don't think the SR would take so kindly to that. (The main issue seems to be that the car starts reporting range and % charge remaining incorrectly, and I think this may be what was behind two or three incidents on YouTube where drivers of LFP-battery cars ran their batteries flat because the reported range dropped from 15 miles to about 4 miles very suddenly.)

But for charging at home, the SR is brilliant. I just drive mine until I reach the point where I think I'd rather not leave it with so little range in case of eventualities, or I have a longer trip the next day, and then charge to 100%. No worrying about stopping at 80%.

There is another advantage the NMC has though. As well as having a longer range, it charges faster on a DC charger - the MG LR battery has a max of 140 Kw as opposed to the SR's max of about 88 Kw. So if you do use the SR for a long trip, then you have to stop more often and these stops will be a bit longer.

For me, I do long trips very infrequently, and wasn't fussed about an extra stop or a bit longer in the café when I did. 99% of the time I am never going to drive beyond the practical range of the car, and I really couldn't justify £2,500 extra for the LR battery.

Also, the LFP lets you be smug and superior because it doesn't contain cobalt.

I think the SE SR is great value for money, but the NMC battery is a good product, it's serving many people very well indeed, and if you do want the extra bells and whistles on the Trophy (and can afford them), then I don't think you should really let the battery put you off too much.

Thanks for the comprehensive reply As you say I guess if they weren't safe they'd soon be taken off the road and I would prefer the trophy spec with the extra bells and whistles.

 

[Rolfe]

I personally prefer the SR, it suits me very well and I don't want most of the bells and whistles on the Trophy. But I don't think the LR battery is going to be hard to manage, and the dangers of charging it up to 100% when you need to do that are well over-exaggerated. The SR battery certainly has a longer life, but the LR will probably outlast the car too if you're merely reasonably careful most of the time.

These fires have to be put in the context of the number of EVs on the road, which runs into many millions. It's still a very rare occurrence. And not to be too ghoulish, but people are killed in vehicle fires when they crash ICE cars too.

From the point of view of public policy, there is quite a lot to be said for skewing the percentage battery use much more to the LFP overall, minimising fires on a global basis, even though the risk to one individual owner is minimal, and minimising the use of cobalt. And as battery technology advances, so will the capabilities (and safety profiles) of both battery types. But when you're buying a car right now, you choose from what's available, and I don't think the risk of fire on its own is large enough to turn people away from NMC batteries if the car is otherwise what they want.

 

[Eber]

In my opinion all this does not matter in real life and I don't spend one second thinking about it. There are Tesla Model S around in the wild from the very first generation with the very first battery pack. There is a Model S with one million miles on it. Regular Joes will never suffer battery problems if they don't rack up a hundred thousand miles per year.

Here is a video (in German) about a BMW i3 with more than 100,000 miles on it. Just look at the diagram at 20:45. The usable energy is 27,02 kWh (27,2 kWh when new). After five years and over 100,000 miles there is more than 99% of capacity left.

To be completely frank, I don't want to waste my time and mind worrying about that at all. I just drive and charge.

 

[crunchy]

According to the paper "Peter Keil et al 2016 J. Electrochem. Soc. 163 A1872", the degradation (SOH) of LFP cells is not so different from NMC cells at 100% SOC and 25 oC storage temperature. On the other hand, the resistance of the batteries differs. The resistance does not change for LFP cells.

For daily use, I would charge NMC batteries no more than 60% and LFP batteries no more than 70%.

 

[Ian Key]

I'm not disbelieving you about the charging percentages you would use based on the paper you've quoted but it is 7 years old and battery management and design has improved over the years.

 

[crunchy]

On the other hand, I would rather believe a 7 year old article than a producer advertisement. Do you have any more recent studies?

 

[Derek25]

The battery chemistry is irrelevant. If you want longer range and faster charging go for the long range. There's no reason not to charge the car to 100% when you need it. Both battery types will likely outlive the car itself.

 

[Tight Git]

If the extra bits on the Trophy are worth £70 per month to you then get the Trophy, if not get the SE SR.

 

[OriginalBigAl]

So I've been giving this some thought and ignoring for a moment the extra features the trophy has there's a good argument for getting the SE SR purely due to the battery chemistry. As you probably know the SE SR can be safely charged to 100% whereas the LR battery should only be charged to 80% which means effectively the ranges are the same if you want to look after the battery. Also the NMC battery is apparently far more prone to catching fire and when it does it does so in a way that severely restricts your chances of living to tell the tale. Check out this video about this subject.


I'm actually considering changing my Trophy lease order to an SE SR , the SE SR is £70pm less for a start and the range will be fine for our needs and if it's safer as well that's a bonus. Thoughts?

We are going to collect a SE LR at the end of the month and having seen the the video thought , bugger! Sam does go on to say most of the problems are with LG batteries and as of yet I have not seen any reported problems with MG,s and the CATL NCM batteries so I,m not going to worry about it. I will however check the small print on my insurance documents more carefully.
I suppose at the first smell of smoke ,get out, and for peace of mind do not travel on the 6th November each year!

 

[Derek25]

We are going to collect a SE LR at the end of the month and having seen the the video thought , bugger! Sam does go on to say most of the problems are with LG batteries and as of yet I have not seen any reported problems with MG,s and the CATL NCM batteries so I,m not going to worry about it. I will however check the small print on my insurance documents more carefully.
I suppose at the first smell of smoke ,get out, and for peace of mind do not travel on the 6th November each year!

Did you worry about car fires when you bought a car full of a highly combustible liquid? There are now some stats on the likelihood of EVs catching fire. Guess what, it's a lot less likely than if you're sitting on a tank of petrol How Much Should You Worry About EV Fires?

 

[Tig170]

I think the SE SR is great value for money, but the NMC battery is a good product, it's serving many people very well indeed, and if you do want the extra bells and whistles on the Trophy (and can afford them), then I don't think you should really let the battery put you off too much.

According to the paper "Peter Keil et al 2016 J. Electrochem. Soc. 163 A1872", the degradation (SOH) of LFP cells is not so different from NMC cells at 100% SOC and 25 oC storage temperature. On the other hand, the resistance of the batteries differs. The resistance does not change for LFP cells.

For daily use, I would charge NMC batteries no more than 60% and LFP batteries no more than 70%.

.... brilliant write up Rolfe, I note that you've had your 1st service in recent weeks?, did the garage give you a state of health figure (SOH)?, or info as to why the BMS needed updating? ~ the reason of my asking is that I have a cheep dongle (combined with car scanner), and my SE (LFP) at ~10,000 miles is showing a 96.15% SOH, which seem a bit steep?

 

[Buster72]

I personally prefer the SR, it suits me very well and I don't want most of the bells and whistles on the Trophy. But I don't think the LR battery is going to be hard to manage, and the dangers of charging it up to 100% when you need to do that are well over-exaggerated. The SR battery certainly has a longer life, but the LR will probably outlast the car too if you're merely reasonably careful most of the time.

These fires have to be put in the context of the number of EVs on the road, which runs into many millions. It's still a very rare occurrence. And not to be too ghoulish, but people are killed in vehicle fires when they crash ICE cars too.

From the point of view of public policy, there is quite a lot to be said for skewing the percentage battery use much more to the LFP overall, minimising fires on a global basis, even though the risk to one individual owner is minimal, and minimising the use of cobalt. And as battery technology advances, so will the capabilities (and safety profiles) of both battery types. But when you're buying a car right now, you choose from what's available, and I don't think the risk of fire on its own is large enough to turn people away from NMC batteries if the car is otherwise what they want.

My view as well.

 

[Robf]

So my Leaf 1st gen 30 kw 2017 37,000 miles has just gone from 12 bar battery to 11. This after 6 years of charging to 100%. Im gutted

 

[tsedge]

So my Leaf 1st gen 30 kw 2017 37,000 miles has just gone from 12 bar battery to 11. This after 6 years of charging to 100%. Im gutted

Shows just how long it takes even without active thermal management. I think battery fretting is way overdone and we will look back and laugh at what people did in future years. The Leaf is a great car, particularly like the latest version.

 

[crl84]

There's no issue with charging the long-range battery to 100% as long as you're not regularly doing it with a fast charger.

The "catching fire" stuff is clickbait-y nonsense.

 

[MGCamb]

So LR charge to 80% normally; charge to 100 at least once a month or as required.

 

[Derek25]

.... brilliant write up Rolfe, I note that you've had your 1st service in recent weeks?, did the garage give you a state of health figure (SOH)?, or info as to why the BMS needed updating? ~ the reason of my asking is that I have a cheep dongle (combined with car scanner), and my SE (LFP) at ~10,000 miles is showing a 96.15% SOH, which seem a bit steep?

That amount of degradation is quite normal. There's a lot of data out there on Tesla batteries now. Degradation is typically steep in the first year and then flattens out. I tracked my last car over four years (Tesla model 3). It lost around 5-6% in the first year and was pretty flat for the next three. Don't believe anyone that tells you their battery is still at 100% (or a service centre that tells you that).

 

[OriginalBigAl]

Did you worry about car fires when you bought a car full of a highly combustible liquid? There are now some stats on the likelihood of EVs catching fire. Guess what, it's a lot less likely than if you're sitting on a tank of petrol How Much Should You Worry About EV Fires?

I am not worried, but checking your insurance small print for " any" event that may occur could pre-warn you of any potential "computer says no" scenario.