Traction battery charging suggestions

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21KonaER

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When we purchased our 2021 Kona (64kWh ext. range) in Feb 2025, the charging settings were AC: 100% & DC 80%. For the last 8 months or so I've lowered the AC setting to 90% as I've heard that continuous charging to 100% is not the best for the battery, and that last 10% takes almost forever using the 10A home trickle charger. Although there is some ambiguous wording in the Owners Manual about charging to 100% every few months, especially if the battery is regularly discharged down below 20%.
May I ask what are the recommended charge settings among log-term Kona EV owners please?
Thanks, Ian
 
80% to 100% DC charging takes a long time.

I'm lead to believe that 100% AC charging isn't detremental.

But how often do you need 100% charge for a journey ?
 
21KonaER said:
When we purchased our 2021 Kona (64kWh ext. range) in Feb 2025, the charging settings were AC: 100% & DC 80%. For the last 8 months or so I've lowered the AC setting to 90% as I've heard that continuous charging to 100% is not the best for the battery, and that last 10% takes almost forever using the 10A home trickle charger. Although there is some ambiguous wording in the Owners Manual about charging to 100% every few months, especially if the battery is regularly discharged down below 20%.
May I ask what are the recommended charge settings among log-term Kona EV owners please?
Thanks, Ian
Click to expand...

There's a long running thread here about not letting your SOC to go below 40% ... The 12V battery doesn't regulary get topped off when SOC gets below 40%. (Above 40%, this 12V top-off occurs about every 4 hours.) If below 40%, this CAN result in a dead 12V & unable to start your KONA. (I found this out myself with my 2020). I used to allow my SOC to get down to <20% before charging (Home / 240v charger). I don't drive much and seldom need to charge more than 1-2 times per month. After needing to replace my 12V about 3 months ago, I no longer allow my SOC to get below 40-35%. As far as the upper end, I've read here or someplace that when you charge to 100%, the batteries all recalibrate to some extent. So my habit is to charge to 100% about every 5th charge vs 90% on a regular basis.
 
JoeS said:
@Tim94549 , I'm afraid I missed this one and went looking for that thread as I didn't realize the Kona's mindless 12v charging ceased below 40%. Would you be kind enough to provide the link?
Click to expand...

Tim94549

Thread 'Auxiliary Battery Charging - an Observation'

A couple months ago I experienced the Dead 12v Battery issue; unexplainably. I read a lot about how the Battery Saver works - requiring a minimal 40% SOC of the traction battery - it then periodically tops off the 12v Aux Battery. (I had previously allowed by traction battery to get down to around 20% before charging).

So at various times overnight, I get the Bluelink alerts about my doors being unlocked - which they are since it's securely parked in our garage. I get these alerts around 4 times per night (or day - when parked for a long time). The alert times seem to be every 4 hours...
 
21KonaER said:
When we purchased our 2021 Kona...May I ask what are the recommended charge settings among log-term Kona EV owners please?
Thanks, Ian
Click to expand...
@21KonaER Ian, to answer your original question, here's just one of the threads which discusses this topic:
https://www.insideevsforum.com/community/threads/kona-ev-charging-does-and-donts.20345/#post-219664
For battery longevity, keeping the Li(NMC) battery below 55% seems to be the latest thinking based on peer-reviews studies, and easily supports the average daily mileage in the US of around 34 miles (55km). This mileage number is significantly lower in most other countries. No problem with fully charging just before taking off on a long trip.
There is a caveat: my understanding is that our Kona Electric cells are top-balanced, which means it's a good idea to occasionally fully charge the car to 100% (but don't leave it at that charge level!) to keep the cells equalized.
Thanks to @Tim94549's post, there is another caveat about which I just learned: the Kona's mindless activation of the 12v battery charging evidently stops below 40%SoC, so don't leave the door or hood or hatch open if below that.
In my case, I have my charging level now set to 50%, always separately plug in the 12v battery smart float charger, and have no qualms about letting the SoC drop very low; however, since the charging cable is very conveniently located I usually plug the Kona in after my wife returns home as I now use a homebrew off-grid slow-charging stand-alone solar-powered battery/inverter bank.
As far as having sufficient range available for unexpected events, in over 20 years of driving electric (mostly in cars with ranges of 25-60 miles), I have only had one 'unexpected emergency' situation where I had to take a neighbor's wife to the hospital, and that's less than ten miles away. As I tell friends who gasp at the idea of seeing a low SoC: "Think about it, when is the last time you set off on a 200-mile trip not knowing you were going to do that ahead of time?":)
 
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