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Discussion Starter · #1 ·
Would there be any expected detrimental effects of an e-Niro (64 kWh) sat at 99-100% SOC for 7 weeks?

Looking for studies/reputable sources rather than unsourced claims. Thanks.
 

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Probably not, and anyway I don't think anyone knows for sure whether an indicated 100% SoC is a true 100% SoC. It's clear from some EVs that the indicated 100% is really around 95% or so, from a look at cell terminal voltages. No idea if the e-Niro display is like this, but it may well be. It would be nice if all EV manufacturers gave clear and unequivocal guidance as to both what their SoC displays are really showing and also whether charging to 100% is harmful. Very few do either, and not many give the option to only charge to a set level below 100%.

There's also a great deal of myth and rumour about the effect of keeping cells at a particular SoC for long periods. I accidentally left my electric motorcycle battery pack at 100% SoC for several months, was a bit worried about the consequences, so did a controlled bench test to check the actual capacity. It hadn't changed at all, and as far as I could tell the pack was every bit as good as it was before I made this error. That's clearly not a universal proof that doing this causes no harm, but given the warranties manufacturers are providing on battery packs I think that if there was a serious degradation risk they would have built in safeguards to prevent it.
 

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The e-Niro 64KWh actually has a 67KWh battery and keeps a couple of KW either side of full and flat. As to keeping it full, I have only had mine. A year, but seen no drop off and frequently keep it at 100% for a while (not 7 weeks to be fair!)

Why do you want to keep it at 100% for that long?
 

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Discussion Starter · #4 ·
Why do you want to keep it at 100% for that long?
Not by choice, car was hit and rendered undrivable about 1 mile from home after a full charge and has been waiting for parts ever since. Part now available 7 weeks later.
 

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I have no studies to cite, but you could always run the heater to bring the state of charge down a bit if you are worried.
 

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I have no studies to cite, but you could always run the heater to bring the state of charge down a bit if you are worried.
Get the sound track from Spinal Tap on, and TURN IT UP TO 11
 

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Kia e-Niro 4+ Yacht Blue. Jan 2021
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Not by choice, car was hit and rendered undrivable about 1 mile from home after a full charge and has been waiting for parts ever since. Part now available 7 weeks later.
That might actually be the safest state for it to be in.
The real killer of the battery is letting it get fully discharged.
Even in the manual, Kia say that if you are going to lay the car up for several months, charge it to 100% first. That way, as the battery slowly self-discharges (it loses less than 1% per day), you will still be left with a safe amount.
 

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I agree, although I would probably do about 90%.

1% a day is not the case at all - I left mine for a week at 86% - came back, it was at 86%

I think 1% a week is more like it - it’s not draining like a Tesla does.
 

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Discussion Starter · #10 ·
I agree, although I would probably do about 90%.

1% a day is not the case at all - I left mine for a week at 86% - came back, it was at 86%

I think 1% a week is more like it - it’s not draining like a Tesla does.
It's definitely not 1% a day, it's dropped from 100% to 99% after 7 weeks according to UVO and that's with the garage moving it a few times.
 
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