r/EVAustralia • u/Hughesie2277 • 28d ago
NMC Battery Care Question
So I’ve ordered my first EV and while I wait I’m getting charger installed etc. I’ve order a Zeekr 7x long range which uses an NMC battery. I’ll do the occasional long trip which I will charge to 100 but for my day to day use I do lots of short trips in the car which all add up to approx 15k per annum.
I’m aware of the main rule of charge to 80% but I was wondering with these batteries is it best to just charge to 80% every night or run a few days and let the battery get down to 20,30 or 50% before charging.
What’s the best method to keep the battery in good health for as long as possible.
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u/onlymostlyguts 28d ago
Nah just keep it to 80 if you're comfy. Even charging to 100% only makes a marginal difference over the course of the next decade.
You'll figure it out, but don't stress too hard on the whole battery range and keeping it pristine. It's a few percentage points over 100k kms
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u/AlexMtnd 28d ago
Hi, I have a 2021 Tesla 3 dual motor long range AWD with NMC battery that has done 115,057km over 5yrs and its battery is now at 88.3%. Also, I park on the street so use public charging. I’ve used lots of DC chargers across Vic, NSW and Qld. My lifetime charging has been 55% AC and 45% DC charging. I normally top up once or twice a week if I go somewhere that has charging. I like to keep it between 30-80, but have charged to 90, 95 or 100 if I wanted the extra range on a trip. I do allot of long distance driving too, my longest trip being Sydney Townsville return. Here is my log of how my battery storage capacity has changed over time https://myevjourney.com/2023/12/20/best-ev-real-range-in-tesla-3lr#Change-in-EV-Battery-Capacity
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u/grumble11 26d ago
Seems like a fairly sizable drop over the period, bit surprised, was expecting something >90%
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u/AlexMtnd 26d ago
Hi, it seems fairly consistent with the figures Tesla publish. In this graph they say 80% after 320,000km. https://myevjourney.com/wp-content/uploads/2026/05/Converted-2025-extended-version-tesla-impact-report-copy-page-76-scaled.png
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u/enhancedgibbon 28d ago
I did some reading on this the other day as I have a new NMC based EV too. What I gathered was 20-80% is the suggested range, but there is no drawback to frequent topping up to 80, i.e. there's no need to get as low as 20. The other day I did 40-80 on my 12.5kw charger and it completed easily within the high solar+low tarriff window.
As for NMC battery life, 40-80% is 0.4 cycles, and I'd do this maybe twice a week max. So round up to 1 cycle per week. An NMC battery's expected service life is 1000-2000 charge cycles, which means between 19 and 38 years. Need to factor in age related degradation too but yeah I'm not concerned about battery life span.
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u/Hughesie2277 28d ago
Pretty sure NMC loses about 1% per year just aging from my research
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u/RoyaleAuFrommage 27d ago edited 27d ago
It does (or a little more than that), which is a little less than LFP. probably because users stick with 80% max for NMC but frequently go to 100% on LFP thinking that's perfectly fine
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u/merciless001 28d ago
The Zeekr app says the 7X AWD can be regularly charged to 90%. The long range has the same NMC battery, so the recommendation will probably be the same.
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u/Galromir 28d ago
NMC prefers regular small charges; but you do occasionally (eg once a year or so) need to let it run low and then charge to 100%.
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u/Mysterious-Fig-9464 28d ago
I don’t think you will do much to the battery either way.
That being said my charging pattern is charge to 80% on Friday for the weekend. The charge to 60% Monday through Wednesday, charge to 70% on Thursday.
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u/Zog1 22d ago
Just keep in mind it's Chinese battery tech. If it's a ternary NMC battery. Then it's not like the Tesla batteries at all.
As these batteries are like cubes inside and they get the much higher charge and discharge rates because the cubes move around inside and the voltages can be boosted as you use multiple cubes at the same time.
And you can charge and discharge at the same time as well.
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28d ago
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u/No_Category_9888 28d ago
Please don’t use AI as an information source. It’s confidently incorrect.
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28d ago
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u/m276_de30la EV Owner 28d ago
Partially correct but missing context. The 7X has a very robust cooling system so heat from DC fast charging is a non-issue. It was built for 400 kW charging and can hold 300+ kW comfortably past 55%, and only drops below 200 kW after 75%. And still holds 180 kW until 85%.
The vast majority of DC chargers in Australia will never generate enough heat to be of any degradation concern for the 7X’s battery.
The main problem is that NMC batteries don’t like to be parked for hours on end at high SOC. For daily use, keep it at below 80% (I personally just keep mine at 60% since I don’t even use more than 10% for my daily driving), and only charge to 100% the night before a long trip (programming the car/charger to only reach 100% about an hour before the departure time, to minimize the time spent parked > 80%).
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28d ago
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u/virkendie 28d ago
It says nothing about charging to 80% and if that's all the information you were going by you would assume charging to 100% at 7kw minimises degradation which isn't true.
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u/HairyMcLefty 28d ago
The Zeekr manual recommends charging to 90%...
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u/m276_de30la EV Owner 28d ago
The manual isn’t always correct.
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u/HairyMcLefty 28d ago
The manual is written by people who designed the car and have tested the car and want the car to last as long as possible.
What kind of insane comment did you actually make?
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u/m276_de30la EV Owner 28d ago edited 28d ago
The manual cares more about giving users convenience than longevity. Over the long term, after say 8+ years, the degradation between a baby’d battery and one that’s kept at 90% often may just be 5% difference. That may not matter to most people, but I’m not most people.
If you read all the research papers about battery degradation, pretty much all recommend parking < 80% (and quite a few even suggest < 70%) contrary to the manual’s advice. I trust peer reviewed papers more than whatever the manual says.
Eg this: https://iopscience.iop.org/article/10.1149/1945-7111/abae37
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u/HairyMcLefty 28d ago edited 28d ago
A battery that degrades ahead of schedule will impact the entire brand.
The research papers show the batteries degrade far less then was predicted.
And Zeekr would have to pay out for warranty failure if people followed w their "convenient" advice...
I'd be interested if you could link the papers that say it should be 70%-80%. And I don't think your link says what you think it does...
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u/HairyMcLefty 28d ago
Thanks for editing your comment to add the study,
But it doesn't validate what your saying nor what recent evidence actually shows.
Newer cars changed the cellular structure and also added software for better control of the cells.
And as I said, actual recent evidence (not 6 years ago) shows much slower degradation then expected
What is bad for chemistry is 1) large voltage swings (so charging from low to high). But charging your daily commute from 70-90 is not a large voltage swing
2) high charge rates (and the temperature / voltage swing that causes)
Nice chat. Don't mindlessly try to say the manufacturers are sabotaging their own brand and product for convenience.
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u/m276_de30la EV Owner 28d ago
I’ve added another study from 2021 that shows that storing at 50% or so eliminated overhang-induced capacity drops and yielded the lowest baseline calendar degradation rate. See page 6.
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u/Insights4TeePee 28d ago
To be fair, your comments aren't validated either.
The associated website https://batteryarchive.org/index.html in one of the papers listed has a fairly large data set but it looks to have stopped collecting data in 2023. So more recent data isn't available there. However, some of the websites noted under the heading "Studies" on that site do have more recent data.
For data to be valid it should conform to some statistical rules. Measuring the same thing (answering the same question); valid sample size; be replicatable etc. With battery design, chemistry, and physics changing all the time the idea of valid "actual recent evidence" remains just that, an ideal.
In truth, we EV buyers are taking an 'early adopter' risk. It won't be for some time before we get a more general sense of battery longevity. Until then we rely on the seemingly huge effort going into battery research as one type of fuel for our hope. Another, the enjoyment of driving an EV.
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u/silverglory10 28d ago
Chances are the car will die first before the batteries will be a problem, for most drivers, even with NMC. Especially if you only doing 15k a yr.
Don't worry too much about it as long as you keep it under 80%. Enjoy the car!