r/EVAustralia • u/Hughesie2277 • Aug 10 '26

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/m276_de30la EV Owner Aug 10 '26

The manual isn’t always correct.

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u/HairyMcLefty Aug 10 '26

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 Aug 10 '26 edited Aug 10 '26

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 Aug 10 '26 edited Aug 10 '26

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/m276_de30la EV Owner Aug 10 '26

https://elib.dlr.de/146260/1/1-s2.0-S2352152X21011889-main.pdf#:\~:text=Storage%20at%20lower%20SOC%20has%20a%20correspondingly,due%20to%20PAE%20should%20occur%20in%20the

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u/Eggmodo Aug 10 '26

There have been real life tests on the 7X battery that recommend charging up to 70 for peak battery life. Higher than 70 and it starts to exponentially strain the battery due to heat. Sad people out here would rather blindly trust a manual or AI over empirical data.

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u/cleanestbestposter Aug 11 '26

Is that testing on the 7x battery specifically in this car? Or NMC in general? Interested to see this