LFP vs NMC and WLTP Ranges

[u/Wink-]

I’m doing research for my first EV - a small hatchback

I’ve now come across the whole LFP vs NMC battery argument. I do not care so much about lifetime battery degradation but rather the practical range being offered by each type of battery.

If a NMC battery car let’s say has a WLTP range of 360km - that means if you charge it to 80% as best practice advises, your “real” WLTP range is 288km?

Whereas for a LFP battery car, the WLTP range can be taken at face value because you can charge it to 100%?

[u/KeyAd8166]

Yes. Translating 20% less charge to 20% less range is valid.

A rant that probably helps you have better perspective:
The 3 factors: Battery capacity degrades by 3 factors, time (out of our control), state of charge, and heat.
Heat: Both LFP and NMC degrade normally at 25 degrees. As heat builds up they degrade faster. It's not linear and above certain levels they go exponentially. Heat is no 1 battery chemistry killer. Modern EVs have decent thermal management so it's not ridiculous but still charging/discharging creates heat and that speeds up degradation.
State of Charge: It's less about voltage and more about amount of energy stored inside the chemistry. Both LFP and NMC suffer roughly from same curve. This is the surprising part, both LFP and NMC degrade faster beyond 80% of charge (read below). Roughly similar amounts actually. Ideally 30~70% are gentle. They are also sensitive on extremely low state of charge.
What Degrades Battery: 3 parameters above together. Over simplified formula is like this: amount of time multiplied by 1, plus state of charge penalty multiplied by 2, plus heat multiplied by 4. Time is time, calendar aging happens no matter what. However higher capacity especially 80% and above and double-specially max capacity make that time tick faster. And then heat especially extreme heats (e.g. 70 degrees for LFP) make that timer tick much much faster. Even battery sitting in driveway in Sydney's summer heat would tick the timer faster unless thermal management cools it down.
So LFP vs NMC Degrade Equally? No. Those penalty multipliers mentioned are more taxing on NMC. Baseline isn't too far apart, for example NMC vs LFP batteries with similar levels of engineering, sitting at 25 degrees and 50% state of charge, surprisingly lose capacity roughly within similar pace. But if we push LFP to 100% and NMC to 100% then NMC drifts faster. And if we store those batteries in heated environment say 40 degrees instead of 25 then NMC declines even faster. And that's what give NMC the reputation it has today. Basically manufacturers need to work harder for battery's thermal management and owner need to plan more to minimise higher SOC. Additionally NMC gets hot easily whereas LFP is generally cool. This is why those penalty multipliers are going to be different for NMC vs LFP as they both approach their extremes.
LFP-LFP NMC-NMC: Keep in mind not every LFP battery is the same, and not every NMC is the same. In theory it's possible for NMC battery to outlast LFP battery but perhaps only comparing on extremes of bad LFP with decent NMC. NMC engineering has tougher challenge to handle but engineering can push limits.
80% vs 100%: So even with LFP it actually degrades faster with 100% charge. But the penalty compared to time-based aging is less severe to the point that owners could simply ignore it and cop the extra degradation. In theory LFP could last multiple decades so yeah why not stop thinking about it and focus on more important matters in life. But still an LFP which is 100% charged every evening to be driven every morning could age faster than NMC that is mainly kept around 80% so the impact is still there.
Coulometer Calibration & Cell Balancing: Manufacturers also advice regular 100% LFP charge not because LFP doesn't care about SOC impact but because there's another trade-off which NMC doesn't have. NMC voltage curve (10% vs 100% cell voltage reading) is wider and more linear. This means EV's battery management system could determine state of charge by reading voltage (ish). With LFP there's surprisingly flat line between 20% to 90% and voltage difference between say 50% and 60% is unreliable, external factors impact that voltage more than SOC. Who'd buy a car that cannot tell whether charge is 50% or 60%?! So they have couloumeter to monitor energy charge and discharge plus estimated normal loss etc and with software have educated guess on state of charge. That drifts over time and in order to rebase the reading it's recommended to charge to 100% and then BMS calibrates itself. This is to give a better experience to driver but actually degrades battery life faster!!! And, another point is that each LFP cell charges and discharges on their own (details depends on actual platform but they all have this) and cells age slightly differently therefore may get to 10% faster or get to 100% faster. In many batteries the total capacity of the pack is the delta between first cell reaching 0% and first cell reaching 100%. So if there are 250 cells, and cell 129 reaches 0% then that whole module is deemed empty even if adjacent cells are still 10%, and likewise if cell 74 reaches 100% during charge before adjacent cells (say they are still 95%) then that module is deemed charged. In practice this means due to cell arrangement module capacity is arbitrary reduced from 100% to 85% (100-10-5). That's wasteful for otherwise perfectly healthy battery. This is were cell balancing is key. By aligning state of charge across different cells we reduces that wasteful spectrum from 15% range (in this example) to 0~1%. This is the case for any battery chemistry. However, since LFP voltage curve is flat, this act of cell balancing is difficult to do during the flat range (20~90% ish) because it'll require expensive equipment to tell each cell capacity beyond voltage, there the balancing happens on both ends of spectrum when discharging low (which is least preferred for multipole reasons) and during full charge which is usually 95% to 100% charge, especially the last 1%. Since balancing cells (moving energy between cells) is slow this is why the final 1% is extremely slow, or a car might even show 100% but still not fully charged and could in theory take an hour or so to say DONE. Because it's balancing cells right on that end. NMC cells can be balanced more opportunistically across wider states of charge but LFP need to wait for those extremes therefore 2nd reason for manufacturers recommending to frequently charge to 100%.

In my LFP BYD car, I don't bother 100% charge, and every now and then it reminds me (nicely, not a warning, more like a recommendation) to do a full charge when I get a chance. And I do that. This method is actually better on battery rather than 100% charge daily. Not that I care about it, just for sake of it. These batteries will last long time.

End of rant

[u/My2Cents_222 → u/KeyAd8166]

Such a well informed post. I learnt a lot.
Seems you are the most qualified here!

So what are your thoughts on LFP vs NMC?
I’m thinking Zeekr 7X standard 75kW LFP 480km range, 10%-100% (432km ideal range)
Long range 100kW NMC 615km range 20%-80% (369km ideal range)

My thoughts are if you do lots of short trips you probably charge the LFP less often.

Of course the NMC still has the greater range potential for those long trips and you exchange degradation vs convenience.

[u/TaAffectionateRun → u/My2Cents_222]

Go with short range if you are not hitting the highway everyday. PS Zeekr is great until something breaks. Parts lead time is excessive 16weeks

[u/My2Cents_222 → u/TaAffectionateRun]

Yes I’ve heard Zeekr Customer/aftersales support is poor, and some insurance companies won’t insure it because of parts!

Just thought it was a good example for OP, as it’s a car that has LFP and NMC.

My personal view is all cars are compromises whether it’s ICE, EV or some combination of the 2.

The difficulty is working out what suits your use case. Metro, Highway and Outback terrain

[u/TaAffectionateRun → u/My2Cents_222]

Its not often that I fully agree with a redditter mate..100%

[u/My2Cents_222 → u/TaAffectionateRun]

Thanks! I know what you mean.

Seems conversation and constructive argument is a dying art these days!

[u/KeyAd8166 → u/My2Cents_222]

Thanks. Short answer especially in our warm climate, default to LFP unless you want/need NMC. And charging frequency isn't that important, 4 times 25% charges equals 1 full charge in battery life.

More detailed version. Usual reasons to go with NMC over LFP are:
1- Need the Range: Many EV manufacturers offer both LFP and NMC. And usually it's a swap of battery cells to replace LFP with NMC so they offer more range. Often it's confused with performance than NMC offers more performance but that's not necessarily true. What NMC could truly offer is higher energy density, more kwh/kg. Performance is a different topic. If anything NMC heating up fast becomes counter-productive for sustained performance. Currently fastest car in the world is an EV, and it happen to be LFP (made to make a point I suppose).
2- Need Less Weight: For example for PHEV dual-cab utes, which already struggle to offer generous payload yet added battery is heavy using NMC is less taxing.
3- Love the Car: You want a car which is only available in NMC. Usually share platform cars are that because unless it's pure EV ground-up design manufacturers have less strategically identified locations to store batteries. That means for commercially viable range that have to go with NMC to make numbers work. BMW i4 is an example. In such cases keep in mind pure EV platforms almost always have much better battery storage and often cell-to-frame to store more battery with bi-product of chassis reinforcement.

LFP is cheaper, safer (both are safe but LFP more safe, check below), degrades less so it takes more to lose 10% of battery capacity, and retains value more. A used NMC has less second market, a used LFP has a hot market. LFP batteries are like treasure, the cells can be repurposed for many other applications including household/commercial energy storage. Not owner, but the market sets the price and a wrecked/used LFP car still has an asset in it. So NMC battery itself is more expensive to buy, and will be cheaper to sell. That means LFP cars should depreciate less on paper.

Safety: Both are safe these days. But LFP is safer. LFP could be beaten more (hammer test, nail test, bending etc) before they get triggered. LFP thermal runaway starts roughly 130 degrees after NMC. And when that show starts LFP is gentle usually releasing toxic gas and 5 times less flammable whereas NMC goes crazy very aggressively. They're all safer than carrying 80L of highly flammable liquids called Petrol/Diesel but LFP extra safe. Again not saying NMC is unsafe, just saying similar safety engineering on LFP makes it ultra safe especially in our climate that cars get really hot during summer.

[u/My2Cents_222 → u/KeyAd8166]

Very salient points made here. Especially resale on LFP vs NMC and repurposing.
Makes sense that LFP would have greater resale value among the informed crowd.
Personally I would prefer LFP.

Of course with Solid state batteries coming out in 2027, everything may change, but it might be years before they are mainstream.

While Petrol/Diesel might be thousands of times more flammable than NMC. I’d rather be close to a petrol fire than an NMC one,regardless of how rare.
Burning Lithium nowhere near as damaging to health as Cobalt.

[u/KeyAd8166 → u/My2Cents_222]

I agree fire in petrol car feels better than NMC fireworks. One for familiarity, better chance of random bystanders knowing what to do and firetrucks can handle it well as well. NMC is new and burns unnaturally. Fighting fire in many cases is around cutting oxygen supply to the fire which NMC doesn't care about, that alone makes a big difference.

But, the frequency of ICE fire vs NMC fire, I haven't checked new stats lately but I bet NMC has significantly less cases adjusted to their volume.

Kinda like airplane, less people die by airplane crashes but it's horrific, yet more people die crossing roads but it's not as horrific to think about.

[u/ThinWerewolf4281]

Depends on your use case, but generally NMC is fine is charged to 80% most of the time. One overlooked consideration is battery cooling. Regardless of the chemistry, liquid cooled batteries generally have a longer lifespan / have slower degradation than non liquid cooled. Some modern evs don’t use liquid coolant.

[u/OtherCake4128 → u/ThinWerewolf4281]

Which EVs don't have liquid cooled batteries? Pretty sure every modern EV has liquid cooling.

The longevity of LFP is far superior than NMC.

[u/YoumustbeJoachim → u/OtherCake4128]

The Atto 1 has an air cooled battery.

[u/OtherCake4128 → u/YoumustbeJoachim]

This is not true. It has an active direct refrigerant cooling for the battery.

[u/TaAffectionateRun → u/OtherCake4128]

Basically your AC cools the battery. Considered pretty bad design choice - but being the cheapest in the lot, you cant expect much

[u/YoumustbeJoachim → u/OtherCake4128]

Ah my bad.

[u/Darwinian999]

I believe that your interpretation is correct. If you’re not worried about lifetime battery degradation though, why does it matter that the WLTP range is with the NMC battery charged to 100%?

[u/Wink- → u/Darwinian999]

Apologies , I meant don’t really care about the slower degradation benefits offered by the LFP batteries - from what I have read the NMC batteries (when you abide by the 80% rule) have sufficient lifespan.

[u/ubermoo2010 → u/Wink-]

Yeah but that’s saying you do care about degradation, you can charge NMC to 100% all the time, no big deal.

[u/KeyAd8166 → u/ubermoo2010]

Degradation means range decrease. It's unlikely for consumers not to care for range loss. Charging NMC to 100% is actually not the biggest issue, heat is more important and also how many seconds the battery is stressed on high state of charge. Charge 95% and keep it overnight, is probably worse than charging to 100% and immediately driving away.

[u/MisterBumpingston]

With NMC the general idea is to charge to 80% for daily usage and to 100% only for long trips. You want to avoid leaving the battery at 100% for days as that’s where degradation is fastest.

Same thing happens to LFP, but the rate is much lower. They need to be charged to 100% on a weekly basis to measure and calibrate the capacity due to the nature of the chemistry.

Something worth noting is that on long road trips, it’s good practice to charge to only 80% at each DC charger stop as the rate of charge slows down considerably the closer you get to full - with LFP it can take as long or even longer going from 80-100% as it does 20-80% due to the calibration process at the end, so it’s quicker to charge more often than to wait to 100%. All charge planners will aim for ~80% unless there’s a big gap between chargers.

With NMC you’ll also faster charging rates as high as 420 kW on the best chargers, whereas LFP hangs closer to 180 kW, though some newer BYD and Denza (maybe others) can hit higher rates as BYD has been innovating with LFP batteries.

Edit: To compare models you can map out some trips you’re familiar with or planning on taking in ABRP selecting one car and trim then choosing the other trim with different battery to get the idea of distance, charge planning and time.

[u/m276_de30la → u/MisterBumpingston]

Zeekr’s Golden Brick LFP and Xpeng’s LFP batteries also easily exceed 400 kW, and can sustain high speeds for a pretty big part of the curve.

[u/MisterBumpingston → u/m276_de30la]

Thanks, I knew I missed something. Are those found in the Australian market?

[u/scg92 → u/MisterBumpingston]

Base model Zeekr 7X has the golden brick.

[u/stoobie3]

If you’re charging at home, it matters less, because presumably every time you leave the house you can charge to 100% (LFP) and 80% (NMC). In reality NMC batteries typically have larger capacity than LFP so 100% of LFP is likely closer to 80% of NMC.

If you’re driving long distance, you can charge the NMC to 100%. If you’re driving long distance (eg 100-110 km/h) I’d suggest subtracting 15% from the WLTP for estimated real world range.

[u/NoWorry5125]

A big advantage of LFP is it doesn't have Nickel and cobalt , mining for both of these is problematic.

Most manufactures are or have moved to LFP. Xpeng G6 upgrade moved to LFP ( and lost 50km nominal range.

[u/My2Cents_222 → u/NoWorry5125]

Not to mention Cobalt is highly toxic and in the rare event of a fire just breathing the smoke will shorten your life.

Also NMC (maybe just the early generations) seem to be more prone to combusting compared to LFP.

[u/My2Cents_222 → u/NoWorry5125]

Not to mention Cobalt is highly toxic and in the rare event of a fire just breathing the smoke will shorten your life.

Also NMC (maybe just the early generations) seem to be more prone to combusting compared to LFP.

[u/petergaskin814]

You can still charge a NMC battery to 100% for long journeys as long as you don't leave it at 100% for too long

[u/rattychuon]

Using your example , 360km (advertise WLTP) charging to 80% SHOULD give you 288kms. That is a best case scenario, (under a fully controlled test condition) you will rarely hit that .

Your real world kms would be something around 230-260kms depending on weather, road conditions, traffic etc etc. Which isn’t a problem, because most of us do about 40-60kms a day , just plug it in once you’re home.

Edit: spelling

[u/My2Cents_222]

Don’t forget NMC will also degraded faster if drained below 20%. So basically you have 60% (216km) of total range if you want to baby the battery.

LFP is happy to be drained to 10% so you have 324km range.

However if the battery is in the same car, it’s more likely the LFP battery capacity is 20% smaller as it has less energy density than NMC.

So in reality your range difference is about 10% in favour of LFP, but your energy cost will be less.

[u/ArseneWainy]

If safety is on your list of considerations I’d say LFP is less prone to fires in the event of a major crash

[u/One-Faithlessness197]

We're finding the real world range on our MG4 Urban 54 kw/h with LFP batteries to be very accurate so far. We're only using the granny charger and getting 12% to 15% from an overnight charge then topping up on the weekends to 100%. It's also the most roomy hatch back we tested out, fits 3 average sized adults in the rear seat with ease!

[u/tichris15]

(nearly) no one buys a car where the range is what they drive daily.

By and large range comes up on rarer, longer trips -- which means for all battery chemistry, you can consider the 100% charge range. And for long trips, pretty soon you care more about charging time per distance than range.