MG4 Battery Degredation

[Tig170]

This was hidden away on another thread, so thought I'd create a new discussion topic (hope this is okay). ABRP now supports (paid version) OBD Live data for the MG4 (I use the - NEXAS NexLink Bluetooth 5.0 OBDII Scanner for iPhone & Android). My car is 6 months old, with 6400miles, and is the LFP (51Kw SE) version: Its reporting a 2.7% degredation, which is a bit higher than I was expecting, given that the LFP is supposed to be more resilient. Cleevelys 51000 mile MG5 (with a NMC ) only had a 3% degredation, should we be worried?

 

[Ayoull]

This was hidden away on another thread, so thought I'd create a new discussion topic (hope this is okay). ABRP now supports (paid version) OBD Live data for the MG4 (I use the - NEXAS NexLink Bluetooth 5.0 OBDII Scanner for iPhone & Android). My car is 6 months old, with 6400miles, and is the LFP (51Kw SE) version: Its reporting a 2.7% degredation, which is a bit higher than I was expecting, given that the LFP is supposed to be more resilient. Cleevelys 51000 mile MG5 (with a NMC ) only had a 3% degredation, should we be worried?

MG4 SE SR
2620miles

1.8% degredation

 

[Macadoodle]

Hmm, slightly concerning considering that the promised longevity is the main reason I went for the LFP pack
Haven't measured my car's SOH, all I can say is at 3500 miles and 4 months it takes 51 kWh from the wall on an overnight full charge from 10%.
That's a figure I've been getting from day 1 and would suggest around 46kWh is going into the pack if there's 10% charger losses, seems fine to me.

I have only AC charged, and only at 4kW as I haven't got around to running an uprated cable out to the garage as yet, maybe this regime is helping the pack in mine

 

[tsedge]

It is normal for all lithium batteries to lose a bit in the first year, up to 10%, though typically a lot less. The curves then flatten a LOT, especially for LFP.

 

[Tig170]

It is normal for all lithium batteries to lose a bit in the first year, up to 10%, though typically a lot less. The curves then flatten a LOT, especially for LFP.

I really hope it flattens a LOT! - the only slight problem is that (and yes we are not comparing like with like), but I have LFP home battery storage (a small 7.5kw system), which charge cycles almost daily (95%-5%), charging every night, and that is showing zero degredation (for the past 6 months!), one does wonder if us LPF owners should be operating more in the 20-80% range, rather than the default charge to 100%, which the app defaults to (I'm pretty sure in the 1st month though, i had a slider which could set to 80% charge upto?)

 

[tsedge]

I really hope it flattens a LOT! - the only slight problem is that (and yes we are not comparing like with like), but I have LFP home battery storage (a small 7.5kw system), which charge cycles almost daily (95%-5%), charging every night, and that is showing zero degredation (for the past 6 months!), one does wonder if us LPF owners should be operating more in the 20-80% range, rather than the default charge to 100%, which the app defaults to (I'm pretty sure in the 1st month though, i had a slider which could set to 80% charge upto?)

Home batteries are far higher quality than car batteries, they have to be to stand the number of charge/discharge cycles.

Also, it will depend how degradation is being measured, which might be different.

100% charge is better for LFP than 80%, it is not that.

 

[Tig170]

Home batteries are far higher quality than car batteries, they have to be to stand the number of charge/discharge cycles.

Also, it will depend how degradation is being measured, which might be different.

100% charge is better for LFP than 80%, it is not that.

Thats what I'm hoping, ABRP has only just come out for support for the MG4, and for all we know they are using a simple algorthym, nevertheless its an interesting one.

This EV, after 89,000 miles reported zero degredation, as the capacity started off at 105% - or words to that effect.

 

[G48MG4]

440 km and 1.7 % degradation for my SE SR.
What confused me a little bit, was the hv battery voltage of 343 V. What is your hv voltage?

 

[Diggsy]

Do we know if ABRP is reporting this accurately on the MG4? It’s such a new platform and other software / hardware doesn’t seem to support it, so I’m wondering how accurate ABRP is, and if it’s actually a concern at all…

 

[Tig170]

Do we know if ABRP is reporting this accurately on the MG4? It’s such a new platform and other software / hardware doesn’t seem to support it, so I’m wondering how accurate ABRP is, and if it’s actually a concern at all…

No we dont, hence the reason for reaching out to gather thoughts!

440 km and 1.7 % degradation for my SE SR.
What confused me a little bit, was the hv battery voltage of 343 V. What is your hv voltage?

attached - mines the 6400 mile, SR LFP

 

[Diggsy]

No we dont, hence the reason for reaching out to gather thoughts!

attached - mines the 6400 mile, SR LFP

Will be interesting to see the results coming in

 

[tsedge]

It is worth remembering that the range of ICE cars also decreases with age. As the engine ages, it becomes less efficient and the mpg drops off. It is generally a slow and small effect, but it is present there too.

 

[Tig170]

It is worth remembering that the range of ICE cars also decreases with age. As the engine ages, it becomes less efficient and the mpg drops off. It is generally a slow and small effect, but it is present there too.

It sort of does, but not quite the same in that my car prior to the MG4 is a 170,000 mile VW Tiguan (I have full workshop diagnostics from official VW Indepedent workshops via ODIS/GEKO), so yes I do maintain it (according to milage/VAG), but its still running at 100% - clearly I'm an exception for car maintence, but nevertheless degredation of 2.7% in 6 months is worrying (especially as my car isn't leased)

 

[tsedge]

It sort of does, but not quite the same in that my car prior to the MG4 is a 170,000 mile VW Tiguan (I have full workshop diagnostics from official VW Indepedent workshops via ODIS/GEKO), so yes I do maintain it (according to milage/VAG), but its still running at 100% - clearly I'm an exception for car maintence, but nevertheless degredation of 2.7% in 6 months is worrying (especially as my car isn't leased)

Possible degradation (and we don't know that it is - could be measurement calibration or error) of 2.7% in 6 months is nothing to worry about. The curves of LFP and NMC batteries are well known and across a whole range of vehicles lithium batteries longevity have been much better than people generally expected.

There is no good reason to worry about degradation unless you have a battery that is not thermally managed - like a Nissan Leaf. They have suffered badly from it but modern EVs with thermal management are far better.

 

[bowfer]

Crikey.
Cleevely recently reported a Tesla with 180000 miles and only a very small percentage loss….

 

[tsedge]

A minimum expected cycle life for LFP batteries is around 3,000 cycles. A cycle in the case of the MG4 SE is (rough medium) 180 miles, so you can expect to get 540,000 miles before you need to replace it.

Now let's suppose you only get half of that... you are still doing better than your VW.

 

[bowfer]

There is no good reason to worry about degradation unless you have a battery that is not thermally managed - like a Nissan Leaf. They have suffered badly from it but modern EVs with thermal management are far better.

Where do you get this from?
I’ve been a leaf owner and member of forums since 2016.
Yes you’ll get the odd story of battery degradation, but you also get stories of astounding battery life.
Leaf taxis are plentiful, and very high mile examples are everywhere.

 

[tsedge]

Where do you get this from?
I’ve been a leaf owner and member of forums since 2016.
Yes you’ll get the odd story of battery degradation, but you also get stories of astounding battery life.
Leaf taxis are plentiful, and very high mile examples are everywhere.

I get it from the FACT that Leafs suffer much more degradation through their lack of thermal battery management. There are plenty of stories of people with only 40-60% of life left after long ownership (yes many years). The fact that this STILL takes a long time to happen doesn't mean it doesn't happen.

You are quite right that this isn't a reason not to own a Leaf. But it is true nonetheless.

Edit: Here is one of a zillion articles about exactly this:

A Study on Real-Life Nissan Leaf Battery Deterioration

The new 40 kWh Nissan Leaf has a real-life range of 170 miles (160 miles in summer and 180 miles in winter). But how does this range change over your first few years of car ownership?

www.nimblefins.co.uk

 

[bowfer]

I get it from the FACT that Leafs suffer much more degradation through their lack of thermal battery management. There are plenty of stories of people with only 40-60% of life left after long ownership (yes many years). The fact that this STILL takes a long time to happen doesn't mean it doesn't happen.

You are quite right that this isn't a reason not to own a Leaf. But it is true nonetheless.

 

[tsedge]

See above in the edit for evidence. There's a load more articles on this.