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Discussion Starter · #1 ·
I have set my EV6 setting such that it stops charging at 90% as I don't really need a top up to the full 328 mile (summer) 240 mile (winter) range. I very rarely charge "on the road" and 95% plus of my charges are on a 7 kWh charger at home.

On those rare occasions where I have a very long journey I made a temporary change to 100%.

  • Is this still something that helps with battery life, or is this a thing of the past?
  • Any other tips for preserving battery life long term?
 

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I have set my EV6 setting such that it stops charging at 90% as I don't really need a top up to the full 328 mile (summer) 240 mile (winter) range. I very rarely charge "on the road" and 95% plus of my charges are on a 7 kWh charger at home.

On those rare occasions where I have a very long journey I made a temporary change to 100%.

  • Is this still something that helps with battery life, or is this a thing of the past?
  • Any other tips for preserving battery life long term?
It's a bit of an urban myth. The battery management is so sophisticated that it looks after the battery better than a nanny with a newborn. The battery is rated at,say 77kw, and 100% charge is 77kw on the infotainment readout, but battery capacity is actually 85kw or thereabouts. The difference between the 2 is the buffer in order to preserve the battery life and save you having to figure out what 90% is. The best preserver of battery life is to NOT use fast chargers exclusively, if you must, then try and charge on a slow charger once every 6 weeks or so. This 'balances' the battery cells and prolongs the life, though if I'm honest, I think you might be over worrying, you won't need to think about the batteries for more than 15 years. Just plug, charge and enjoy the drive.
 

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Discussion Starter · #4 ·
It's a bit of an urban myth. The battery management is so sophisticated that it looks after the battery better than a nanny with a newborn.
Just plug, charge and enjoy the drive.
To be fair that is exactly what I did with my 2017 Nissan Leaf. Charged to 100% every night and after 66,000 miles and 4 years of use the battery still had all 12 bars.

However this is the official guidance from the Kia manual.

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Yes, it's the right thing to do on the EV6 chemistry. You could even reduce that to 80% if you were being Uber conservative but not if that then means you're frequently using the bottom 20-30%. On most (cobalt) chemistries, keeping between 20-80% is pretty good for battery life.

The latest LiFePO4 (LFP) chemistry is a bit .ore forgiving, and ultimately it's all a question of longevity that is probably beyond the concerns of the first owner, and probably the second...

It's a bit of an urban myth.
Err, it's really not.
 

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To be fair that is exactly what I did with my 2017 Nissan Leaf. Charged to 100% every night and after 66,000 miles and 4 years of use the battery still had all 12 bars.
That's a.bit different, as doing 16,000 miles a year you were rarely if ever holding the car at a high state of charge and cycling 100-20% is better for everyone than running 80-0% every day.

The issue with batteries isn't so much charging to 100%, it's holding them there for prolonged time. I get the impression OP isn't do massive daily mileage.
 

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Discussion Starter · #7 ·
Thank you. Yes. As original poster (OP) I can confirm a daily average of around 50 miles with occasional longer journey.
 

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I'm doing exactly the same as you, Warwick.

But having said that we also have a 6 year old Leaf that we always charge to 100% (we need all of that 70 mile range!). We've never DC charged, only AC. The Leaf is still showing all 12 capacity bars.
And that battery technology is basically 10 years old, so must be better now.

Apparently frequent, fast DC charging is the worst thing for battery longevity..according to Kryten at Fully Charged.
 

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90% is good from a regen perspective. Rapid charging is the one that really affects the battery life. Level 2 chargers are relatively fine and even occasional 100% is also good for rebalancing. Some say occasional drop to less than 20% also helps but not sure.
 

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The suggestion in the manual of the Kia e-Niro is to charge to 100% once a month. As far as I know the cells are only balanced when charging to 100%. I think the ideal is to charge to 80% if you do not need any more and to 100% once a month. But charge to 100% when you are going to use the top 20% the next day. As already mentioned the worst treatment of the battery is to leave it at 100% for a long period.
 

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Modern battery management systems can balance cells at less than 100%/max voltage, I don’t know why people keep saying it.

Especially when they often also say that 100% isn’t 100% due to battery buffers. How can you charge to 100% when you can’t?!

Just charge it and use it how you need to, let the BMS do its job is my totally free ‘advice’. ;)
 

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Because that's the manufacturers' advice...
Which manufacturer is advising charging to 100% regularly to ‘balance cells’?

And how does that square with the fact that you can’t charge a BEV pack to 100% anyway, Tesla excepted?

Ergo, the BMS can balance at less than 100%.
 

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Which manufacturer is advising charging to 100% regularly to ‘balance cells’?

And how does that square with the fact that you can’t charge a BEV pack to 100% anyway, Tesla excepted?

Ergo, the BMS can balance at less than 100%.
Yes it can, but it'll not balance when it's below its defined 100% SoC. The Kia Connect app even has an indicator on the status screen that indicates 'balancing'. The battery icon will blink or something like that. You can also check what's happening once 100% is reached. You'll see the charging voltage drop since at that moment the BMS starts balancing the cells and will try to bring the lower ones up to the voltage of the higher cells. This process may take a couple of minutes or an hour, depends on the state.

Another indicator that it does not balance throughout the charge is that once cells are un-balanced (check via an ODBC reader), they will remain unbalanced until you charge to 100%
 

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Which manufacturer is advising charging to 100% regularly to ‘balance cells’?
I think this is true for Leafs and Zoes.

However more modern BMS can balance on the fly and don't need to be charged to 100%.

The only thing is does do, charging to 100% after discharge to a low SOC is effectively re-calibrate the BMS to give you a more accurate estimate of total capacity. So it can seem like you've got back more energy (or the battery memory effect).
 

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Yes it can, but it'll not balance when it's below its defined 100% SoC. The Kia Connect app even has an indicator on the status screen that indicates 'balancing'. The battery icon will blink or something like that. You can also check what's happening once 100% is reached. You'll see the charging voltage drop since at that moment the BMS starts balancing the cells and will try to bring the lower ones up to the voltage of the higher cells. This process may take a couple of minutes or an hour, depends on the state.

Another indicator that it does not balance throughout the charge is that once cells are un-balanced (check via an ODBC reader), they will remain unbalanced until you charge to 100%
That’s a conscious choice by Kia, which is fine, but just confirms my point that a BMS can balance individual cells at less than 100%.

I get that Kia call it 100% for ease of understanding by customers, when it’s actually 90% in reality.
 

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I think this is true for Leafs and Zoes.

However more modern BMS can balance on the fly and don't need to be charged to 100%.

The only thing is does do, charging to 100% after discharge to a low SOC is effectively re-calibrate the BMS to give you a more accurate estimate of total capacity. So it can seem like you've got back more energy (or the battery memory effect).
I was thinking of the Leaf when I wrote my question, like so much of what people believe to be gospel truth today re BEV battery management, it seems to stem from that particular vehicle.
 

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I was thinking of the Leaf when I wrote my question, like so much of what people believe to be gospel truth today re BEV battery management, it seems to stem from that particular vehicle.
Yep.

Reading the factory manuals is interesting for the Leaf. They really felt that driven normally you didn’t need active cooling.

The design spec seemed to be for a local runabout, not to be regularly rapid charged.
 
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