LFP or NMC

[JoanGN]

I am looking at a mg4 and I have the doubt between the standard model with LFP battery or the comfort with NMC battery.

The LFP are safer, and can be charged to 100% but they give a little less autonomy. But they start to degrade after 3,000 charge cycles.

The NMC advise charging them to 80% and not go on to less than 20% to extend batery life. They can do about 1,500 charge cycles before degrading.

I calculate that at 100 km/h with the standard you can do about 228 km and with the comfort about 275 km.

What is your opinion?

And which batery you'll choose?

 

[Rip Van]

NCM battery?

 

[siteguru]

If I was only getting 35 km (22 miles) extra from the larger battery I would be complaining. Are you sure you have your calculations right? (265 km = 165 miles ... I'd expect the SR version to get around about that nevermind the LR version)

SR = WLTP 218 miles = 349 km
LR = WLTP 281 miles = 450 km

 

[JoanGN]

If I was only getting 35 km (22 miles) extra from the larger battery I would be complaining. Are you sure you have your calculations right? (265 km = 165 miles ... I'd expect the SR version to get around about that nevermind the LR version)

SR = WLTP 218 miles = 349 km
LR = WLTP 281 miles = 450 km

But do you know WLTP is going at 50km/h speed.

for me the max distance is used when i go on vacations, it mean long roads, travelling at 110 km/h average speed, so at that speed is not 350km SR and 450 LR , is way less.

There is an app: ABRoutePlanner, wich is used to calculate stops on your trips.
There i get those numbers.

Going from 100% charge with LR model, to a place 275 Km far, you end with 10% battery.

Going from 100% charge with SR model, to a place 228 km far, you end with 10% battery.

 

[siteguru]

Per the other thread, ABRP seems to give a pessimistic estimate - probably so nobody can accuse them of making them run out of charge.

 

[Thorpey]

If you are leaving the car for a prolonged period of time it's recommended not to change a NCM battery over 80% but if you are going on a long journey and setting of shortly after charging 100% is fine. The degradation results from leaving the pack at a high voltage, it's fine for short periods of time.

 

[siteguru]

Point of technicality - the voltage is a constant (near enough). I guess you mean leaving the pack with a very high state of charge, which means the electrodes of the cells may start to grow a layer of "oxide", so reducing their ability to discharge the current properly.

But the thrust of your post is correct.

 

[Thorpey]

Point of technicality - the voltage is a constant (near enough). I guess you mean leaving the pack with a very high state of charge, which means the electrodes of the cells may start to grow a layer of "oxide", so reducing their ability to discharge the current properly.

But the thrust of your post is correct.

Incorrect the voltage of the pack increases and decreases with state of charge, this is precisely how you define state of charge. LFP are more resistant to being help at maximum voltage which is lower and therefore they have a lower power density

 

[siteguru]

Incorrect the voltage of the pack increases and decreases with state of charge, this is precisely how you define state of charge. LFP are more resistant to being help at maximum voltage which is lower and therefore they have a lower power density

Every day's a school day.

 

[m4rmite]

I'm guessing it would depend upon your mileage.
Example - 10,000 miles per year circa 200 miles per week.
That would be 1 charge per week give or take.
So if degradation started after 3000 full charges on a lfp battery, that would take 60 years to start degrading per se.
I think trying to make the absolutely right decision can blind our senses sometimes.
The choice will boil down to what suits you best.

 

[Thorpey]

The MG will be our 5th full electric car. At first I was obsessive about the battery in a 21Kwh BMW i3 and you couldn't even limit the charge to a set percentage. I started to relax when I had a Tesla model S that ended up doing 90k miles and stopped degrading at about 92%. I now tend to charge our cars up to 90% and haven't noticed any consequences but I don't do much milage at the moment.

 

[degredilla]

I'm guessing it would depend upon your mileage.
Example - 10,000 miles per year circa 200 miles per week.
That would be 1 charge per week give or take.
So if degradation started after 3000 full charges on a lfp battery, that would take 60 years to start degrading per se.
I think trying to make the absolutely right decision can blind our senses sometimes.
The choice will boil down to what suits you best.

Degradation starts once battery is built, not after X cycles. LFP should reach standard degradation after about 3000 cycles. Maybe 2000 maybe 8000. It depends on too many factors.

 

[Deleted member 9692]

I have a question. On the trophy, which has the NMC battery I think? I will charge at home 99% of the time with a 7kw charger. Some people seem to suggest that it is less harmful to charge an NMC battery to 100% regularly with these chargers than the rapid 43kw+ chargers. Is there any truth in that for an NMC battery or am I reading ill informed opinions?

 

[tsedge]

You can charge both batteries to 100%, that is fine. If you do so regularly with the LR/NMC, it will affect its overall lifespan and in particular you shouldn’t leave it at 100% for extended periods of time.

Lots of rapid charging will reduce the lifespan a little but there are plenty of people who do it regularly with no ill effects.

Modern batteries in general will last several times the life of the car and have future uses. Battery degredation is low and slow and you are protected by the warranty anyway.

I think we are past the point where this makes much difference unless you expect to drive the car well past 100,000 miles.

 

[Thorpey]

I have a question. On the trophy, which has the NMC battery I think? I will charge at home 99% of the time with a 7kw charger. Some people seem to suggest that it is less harmful to charge an NMC battery to 100% regularly with these chargers than the rapid 43kw+ chargers. Is there any truth in that for an NMC battery or am I reading I’ll informed opinions?

This is highly dependant on the battery cooling as it is the heat that damages the battery. It was a big issue for the Nissan leaf which is air cooled but much less for liquid cooled batteries like in the MG4.

 

[dickturpin]

I am looking at a mg4 and I have the doubt between the standard model with LFP battery or the comfort with NMC battery.

The LFP are safer, and can be charged to 100% but they give a little less autonomy. But they start to degrade after 3,000 charge cycles.

The NMC advise charging them to 80% and not go on to less than 20% to extend batery life. They can do about 1,500 charge cycles before degrading.

I calculate that at 100 km/h with the standard you can do about 228 km and with the comfort about 275 km.

What is your opinion?

And which batery you'll choose?

LFP any day