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Hi all
Does anyone know much about cell balancing in the Kona. Due to a change in circumstances in unlikely to need a full charge for a while so only charge to 70 or 80 %. Would an occasional charge to 100 % when I have an immediate use for it be a good move?

Many thanks

Bill
 

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I don't do much mileage and mostly short local trips, so generally only charge from about 50% to 80%. Every couple of months I give it a 100%, but try and do it the day/night before a longer (rather than just local) trip, so it's not sat at very high charge for a long time.
 

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This has been urban folklore from the days of the early Leafs, and may have been beneficial then....but technology has moved on.
Note that the Kona manual recommends this only if the battery has been run right down, and also that the car clearly has a significant buffer at the top end, meaning that 100% isn't really 100% anyway.
Mine has been fully charged (AC) 3-4 times in 15 months, but is normally kept around 50%, the recommended average level for all Li-ion batteries for best life. It has been left unused for 2-3 weeks several times without any drop in SoC, SoC BMS, SOH or range...
 

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My understanding of cell balancing is for accurate reading of SoC and SoH, so occasionally all the cells need to go to 100% to "reset the guage" so to speak. Most of the time my battery sits between 70% - 80% and I go to 100% every couple of months.
 

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I have a 62Kwh LEAF and it usually gets charged over night to say 80 / 90% - using the LEAFSPY APP, it identifies each individual battery cell. Most of these cells get a full charge but there is about 20 % that only get a minimal charge and it always seems to be the same cells probably the way the BMS is set up (my previous LEAF was the same).

My perception is that if these cells are left in this state over a long period of time, then they can become weak and the biggest threat to any battery is weak cells.

I always make a point of charging to 100% once a month and LEAFSPY shows all the cells nice and level.
 

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I haven't charged to 100% for over 6 months now and I believe that is when balancing takes place, if needed. The car has only been charged to 100% perhaps four times since purchase, 20 months ago.
Normally I keep the SoC between 50 and 70%. Now I'm seeing that one pack of the 98 (three physical cells in parallel) has dropped 0.02V below all the others and I will soon find out if that can be corrected with a charge to 100%.
132043
 

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I charge to 100% A lot as I use it mainly for long journeys,

I find on some but not all charges it balances between 95% and 100%... On the ones its balancing the charge really slows down and often shows its going to take an hour or more to do that last 5%..

On a none balance charge its often done those last few percent in 15mins.

There does not seem to be any pattern to it, and once its reached 100% its done Full Stop no real benefit from leaving it plugged in after that.. The reason I say that is on our old BMW i3 it did not balance till it hit 100% and you were advised to charge to 100% then leave it plugged in for a few hours to allow it to balance occasionally.
 

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I haven't charged to 100% for over 6 months now and I believe that is when balancing takes place, if needed. The car has only been charged to 100% perhaps four times since purchase, 20 months ago.
Normally I keep the SoC between 50 and 70%. Now I'm seeing that one pack of the 98 (three physical cells in parallel) has dropped 0.02V below all the others and I will soon find out if that can be corrected with a charge to 100%.
View attachment 132043
It will be interesting to see if pack 57 is a sign of degredation if it doesn't reach 3.74 Volts after a 100% charge.
 

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Here's the previous and the current status after charging to 100% overnight. I'll also note that the resolution of the voltage readings appears to be 0.02 V, so "0.02" difference could actually be far less if voltages are truncated back to the nearest even number at the second decimal.
132125
132124


I'll just add that the BMS SoC was 94.5% at 100% displayed. The Kona is at 14,000 km and 20 months old.
132129


Also, after using 11% of the charge the cell voltages are still balanced within the resolution available.
132130
 

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The Hyundai Kona Electric Manual recommends charging to 100% at least once a month. Presumably exactly for keeping the cells balanced. So yes to your original question.

Conventional wisdom is that storing li-ion batteries charged at 100% is not good for the battery longevity. So ideally do the 100% charge before a longer trip.
 

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The Hyundai Kona Electric Manual recommends charging to 100% at least once a month. Presumably exactly for keeping the cells balanced. So yes to your original question.
The Hyundai Kona Electric Manual actually says:
"If the high voltage battery charge amount is below 20%, you can keep the high voltage battery performance in optimal condition if you charge the high voltage battery to 100%. (Once a month or more is recommended.)"

The manual offers NO specific guidance for owners who keep their battery above 20%, so it is not unreasonable to infer that Hyundai does not have cell balancing concerns for batteries kept part charged above this 20% level.
 

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The Hyundai Kona Electric Manual actually says:
"If the high voltage battery charge amount is below 20%, you can keep the high voltage battery performance in optimal condition if you charge the high voltage battery to 100%. (Once a month or more is recommended.)"

The manual offers NO specific guidance for owners who keep their battery above 20%, so it is not unreasonable to infer that Hyundai does not have cell balancing concerns for batteries kept part charged above this 20% level.
That would fit with the advice from the battery experts who say to keep a lithium ion battery within 20% to 80% for optimal health.
 

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One should bear in mind that manufacturers advice is usually given on the basis of normal use patterns. It is not normal to leave any car sitting unused for long periods - it can cause problems with ICE as well. A couple of weeks a year while on holiday is usual.

I have lithium batteries for an electric outboard. For these normal use includes being laid up for several months over winter. So if they are left unused at a high charge state for a couple of weeks they have a function that discharges the battery (at 100 mA) down to about 60% SoC, and a bit later puts the electronics to sleep to avoid additional discharge.
 

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That would fit with the advice from the battery experts who say to keep a lithium ion battery within 20% to 80% for optimal health.
True, but remember there's already a fairly significant buffer above and below what is used, so the 0-100% we see on the dashboard is probably something like 3%-97%. Still makes sense to generally keep it within 20-80% but at least once per month leave it on for a full charge to 100% with some time to spare for rebalancing.
 
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True, but remember there's already a fairly significant buffer above and below what is used, so the 0-100% we see on the dashboard is probably something like 3%-97%. Still makes sense to generally keep it within 20-80% but at least once per month leave it on for a full charge to 100% with some time to spare for rebalancing.
That's exactly what I do. I'm on an evenings and weekend tariff, so the first Saturday of the month is battery balancing day. :)
 

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You would think that having a warning light or message on the dash would be a useful feature when the difference exceeds a certain value, at a guess perhaps 0.05V. Otherwise there is no need to worry about it.
 
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