Charging Amount is Consistently Dropping Over Last 3.25 Years

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Tim94549

Tim94549

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So MY2020. It was Advertised at over 300 miles charge (maybe more, 325 ?). The amount of charge I'm getting has been consistently dropping since purchase. I now charge to 90% (used to be 80%) because of this drop. I was initially getting close to 275 miles per 90% charge. I am now down to less than 220 miles every charge @ 90%. Granted we're just getting out of winter cold. (Mine is in a garage). I haven't charged to 100% in a long time, but suspect I'd be lucky to get 250 miles.
I know people have said it's "based on driving" habits and this is only a GOM (guess-o-meter) based on habits. But I really don't change habits. I mostly drive around town and only about every 2-3 days at that. An occasionally Freeway drive every week. (I tend to charge about every 2 weeks under normal use). ECO Mode Level 3 Regen all the time.
I don't get why the slow drip drip drip of losing charging maximum. Anyone else seeing this?
 
Tim94549 said:
So MY2020. It was Advertised at over 300 miles charge (maybe more, 325 ?). The amount of charge I'm getting has been consistently dropping since purchase. I now charge to 90% (used to be 80%) because of this drop. I was initially getting close to 275 miles per 90% charge. I am now down to less than 220 miles every charge @ 90%. Granted we're just getting out of winter cold. (Mine is in a garage). I haven't charged to 100% in a long time, but suspect I'd be lucky to get 250 miles.
I know people have said it's "based on driving" habits and this is only a GOM (guess-o-meter) based on habits. But I really don't change habits. I mostly drive around town and only about every 2-3 days at that. An occasionally Freeway drive every week. (I tend to charge about every 2 weeks under normal use). ECO Mode Level 3 Regen all the time.
I don't get why the slow drip drip drip of losing charging maximum. Anyone else seeing this?
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Not at all...
Purchased Nov 20, and still has better than rated 415 km (258 miles).
This morning topped up to 90% and reads 427 km with ambient temps ~6 degrees C. I fully expect over 500 km (as usual) later this spring or early summer.
I am sure your range will p/up once warm weather kicks in. ;)
 
My three year old 2020 model is still averaging 320-340 miles at full charge, well ahead of the EPA range. Living in Hawaii, winter cold is not an issue, of course.
 
electriceddy said:
Not at all...
Purchased Nov 20, and still has better than rated 415 km (258 miles).
This morning topped up to 90% and reads 427 km with ambient temps ~6 degrees C. I fully expect over 500 km (as usual) later this spring or early summer.
I am sure your range will p/up once warm weather kicks in. ;)
Click to expand...

We'll see ... I maintain a spreadsheet on my Charging so once the weather heats back up I'm hoping for some increase.
 
Tim94549 said:
That is amazing. How many miles on your MY2020 ?
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I should have mentioned that my car is very low mileage for its age -- about 13,500 -- so battery degradation isn't an issue. Strikingly, when I moved to my current location my range took a leap upward. I'm in the hills about 7 miles out of town, so my typical shopping/errands run starts with about 6 miles of fairly gradual downhill, which seems to hit a sweet spot in terms of regen vs. consumption.
 
This conversation is getting us to the measurement of the vehicle's battery pack State of Health rather than using the vehicle's (unknown?) algorithm which is affected by way too many variables. Any updates on recommended OBDII hardware and/or bluetooth apps which readily show the pack SoH and individual cell voltages and the usual parameters of interest as well as perhaps calculated driving efficiency with graphs? Prefer iOS, but have an old Android tablet and OBDLinkLX if needbe, but willing to splurge on our 'new' Kona Electric (named 'Konik'). :-)
 
Interesting thread. So I do in fact have a ODBII device (Bluetooth) that shows me the Cell Status of my batteries. I take a snap shot every few months just to maintain a record. So I charged to 100% 2 days ago & checked cells. The thing I note is that they are exactly the same value as they were a couple of years ago (4.16 v << Volts per cell, right?) However at a 100% Charge, my GOM is NOW only 244 miles. However in July 2020, I was getting 310 miles GOM ! This is now a drop of over 65 miles at 100% Charge. This makes no sense to me .. (I tried to insert a pic of the cell status but can't figure out how to do that.)

edit: PS, my MY2020 only has 11,500 miles
 
I haven't seen any significant change in GOM since I bought the Kona in 2018. It was 515 km (322 m) when new and it's stayed between 496 (winter) to 510 (summer). The replaced battery pack in Oct 2022 didn't change anything. My local climate is essentially identical to yours (adjusted for opposite hemispheres in the image), just slightly narrower in span. However ... local speed limits are low, 50 to 80 km/h (30-50 mph) with light traffic. I just drive normally but rarely use (heat-pump) heating or AC. There are no higher-speed roads local to me and that is one important difference. After my most common daily trips the dash reads under 12 kWh/100km (5.2 mi/kWh) which is very good economy. My tires are set to 40 psi. I also don't drive much and only have 26,000 km on it, not that it should affect the comparison.

The normal max cell voltage is 4.16 and I don't think an aged cell would go higher, or lower than the minimum of 3.16 V despite that I suspect some might believe it dynamically adjusts to compensate for natural loss of capacity.

Aside from reading the current SoH value, to properly assess the battery you need to document the pack's 'odometers' CCC, CDC, CEC and CED at both extremes of SoC, as I've posted about several times. One reading at 95-100% (incl displayed SoC preferably to half a percent from OBD) and another set of the same parameters under 15%. It doesn't matter how you drive in between those readings, or how long it takes.

A couple of owners have reported (on FB) reading under 95% SoH but I noted that both live in fairly hot areas, inland SoCal and Phoenix.

upload_2023-4-21_8-51-24.webp
(https://weatherspark.com)
 
I have a 2019 and used to be seeing 285-310miles on 100% charge. now I only see 265mi on 100%. I initially thought its related to the battery recall because my ranged dropped about 10% after battery swap but now I'm getting close to 265mi range and about 220mi real world driving range...
 
Pobre said:
I have a 2019 and used to be seeing 285-310miles on 100% charge. now I only see 265mi on 100%. I initially thought its related to the battery recall because my ranged dropped about 10% after battery swap but now I'm getting close to 265mi range and about 220mi real world driving range...
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There are a lot of variables out there.....Did you get new/different tires, change tire air pressure, different driver or driving habits..and so on? My 2019 still shows about 400 miles @ 100% (based on the previous driving conditions, back country roads and no highway speeds, on the interstate after a 70 mph run for an hour or more, 80% shows about 220 miles, LOTS OF VARIABLES!
 
My 2019 Kona EV is currently at 64,000 miles. I live in SoCal. I only charge my battery to 90%. At 90%, I still get between 287 and 318 miles depending on the outside temperature. In the winter, I get 287 miles at 90%. In the summer (which is at the time I am typing this), I still get 316 to 318 as the day I bought the car. The car is still on the original battery. Hyundai keeps contacting me to change the battery. I want to wait another year until I get around 75,000 to 80,000 miles before making the jump for a new free battery. I hate to see a good working battery going into scrap. The car has 100,000 miles or 8 years of warranty on the battery as I spoke to them on the phone. I have a blue tooth OBDII where I can monitor the voltage of every single cell from my phone. The battery has 98 cells. If I detect any anomalies in the voltage readings, I will have Hyundai change the battery for me right away. Until then, I will keep pushing it as far as I can.
 
Loc Quan said:
My 2019 Kona EV is currently at 64,000 miles. I live in SoCal. I only charge my battery to 90%. At 90%, I still get between 287 and 318 miles depending on the outside temperature. In the winter, I get 287 miles at 90%. In the summer (which is at the time I am typing this), I still get 316 to 318 as the day I bought the car. The car is still on the original battery. Hyundai keeps contacting me to change the battery. I want to wait another year until I get around 75,000 to 80,000 miles before making the jump for a new free battery. I hate to see a good working battery going into scrap. The car has 100,000 miles or 8 years of warranty on the battery as I spoke to them on the phone. I have a blue tooth OBDII where I can monitor the voltage of every single cell from my phone. The battery has 98 cells. If I detect any anomalies in the voltage readings, I will have Hyundai change the battery for me right away. Until then, I will keep pushing it as far as I can.
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Two things to think about:
  • Hyundai want to swap out your battery because a number of units in Korea have spontaneously ignited. I hope that you are not parking your unit indoors!
  • Your Kona like mine (2019 model year) has a lifetime warranty on the battery, so you don't have to worry about changing it out too soon.
 
Loc Quan said:
... I hate to see a good working battery going into scrap.... I have a blue tooth OBDII where I can monitor the voltage of every single cell from my phone. The battery has 98 cells. If I detect any anomalies in the voltage readings, I will have Hyundai change the battery for me right away. Until then, I will keep pushing it as far as I can.
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My old battery was in perfect shape as well but I had to accept that I couldn't drag it out forever and was one of the last in this country to have this done Oct '22. The defect present doesn't affect the battery energy capacity as long as it doesn't fail. My new battery had been waiting in stock, unlike in other parts of the world and was already 10 months old according to the manufacturing tag.

The battery of course really has 296 cells. Each of the 98 "cell" voltages is the combined total of three cells in parallel - with a voltage resolution in 0.02 V increments. One rogue cell would have to "fight" the other two good cells enough to force the combined reading out of the normal range (0.00 to 0.04) and of course these cells have a very low internal resistance so current passing between them would be high. I understand the BMS will trigger a dash warning at 0.1 V deviation which would mean that the defective cell would have to be in fairly bad shape, which I suspect is why they were not able to detect the onset of runaway failure in all cases with software updates. But, I believe that limiting SoC to under 80 or 90% is very effective at limiting dendrite formation from the anode through the separator, which seems to be what causes the leap between the "folded anode" manufacturing defect (clearly visible in the sectional cutaway view of a Bolt cell) and a thermal runaway event, or what engineers call "a fire".

folded anode.webp
 
Here is the power use/cost of my 2021 Kona EV in April @47,810km. (Wide sheet and there are some holes in the info and some weird numbers here and there - I am not perfect )
I normally charge to 80%, which next morning reads as 79%. The green/black character colour change shows switch from ECO to Normal driving. I drive in ECO mode during the winter to have finer torque control om ice. The Kona range, according to government data is 415km. Columns L and M show range extrapolated from to 79/80% SOC to full charge. L with climate ON, M with climate OFF.

Column P shows the hours needed to charge from the dash , I break it out 1/10 of hour.
Column Q is my calculated cost at overnight rate @0.074c/kWh plus including other charges and tax. I came to the actual cost of 0.1275c/kWh
Column S shows what the 'hydro box' calculates as power used. But their price does not take into consideration delivery, tax etc. So again I use 0.1275c/kWh.

OBDII reading @79% SOC shows Max cell voltage = jumps between @39.7V and 37.8V; Min cell voltage @39.6V (solid)

At this point I am not concerned about my HV battery.

Hope this info is useful.
 

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Last edited:
Glenn Gordon said:
Two things to think about:
  • Hyundai want to swap out your battery because a number of units in Korea have spontaneously ignited. I hope that you are not parking your unit indoors!
  • Your Kona like mine (2019 model year) has a lifetime warranty on the battery, so you don't have to worry about changing it out too soon.
Click to expand...
probably not the original owner thats why warranty is as stated.
 
Guys, charge your battery to 100% from time to time to let the BMS know they have a full capacity of 64 kWh.
Also, all the cells of the battery need to be balanced by their voltage on a full charge.

Since you charge your battery to 80% your BMS does not see a fully charged battery and it reflects on your GOM.

Personally, I don't see a problem to charge my battery to 100% frequently. Just don't keep the car charged to 100% for days.
Charge in full and drive on the same day. There is a little buffer even if you see 100% on a GOM.
So 100% is not true full charge :)

Probably you saw that the regen still works on a full charge. It means you have a buffer in your battery capacity.
 
Alex7xl said:
Guys, charge your battery to 100% from time to time to let the BMS know they have a full capacity of 64 kWh. Also, all the cells of the battery need to be balanced by their voltage on a full charge.
Click to expand...
That's not always necessary. I haven't charged past 70% since last Oct and my GoM shows over 500 km at around 16°C battery temp and all cells are in perfect balance. The BMS knows the charge level from the open-circuit pack and cell voltages. I made the graph below based on LG Energy's specifications for the original E63 cell used in the Renault Zoe and Kona.
LG-Chem L63.webp
 
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