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Has anyone reported any battery degradation on their Kona as yet?
Does the battery still appear to be operating at your expected level?
 

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I think @stageshoot is the only person to have hammered his enough to answer that question with any authority (probably over 50,000 miles now).
I expect he'll be along shortly ...
 

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1 year and 20k miles in everything appears fine, kind of tempted to get an odb thing to see what it says
 

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I tried OBD and it simply reports 100% (13K miles). It looks like it never shows anything different unless there is a serious degradation. Some people tried that with brand new car (still showing 100% contrary to some Leafs that reported initially eg. 103%) and maybe @stageshoot could check that after 50k miles?

The only way to measure the degradation is to drive it from 100% to very low SOC (or thereabouts) and simply calculate available KWhs (consumption per km * kms driven / energy used). I hope i got that right :)
 

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The OBD still shows 100% at 54k miles now

as been said it seems on the Hyundai’s it’s more a Good/bad trigger rather than a proper level which is a pity

but being honest the car does not seem to have lost range and it’s difficult to measure the amount of power you put in as you need to take into account charging losses etc

But in a way not having a percentage gauge has stopped me obsessing about SOH. in reality if it was to even lose 30% over 5 years or 150k miles (which I think is unlikely ) it would still have a 200 mile usable range the same as most of the new offerings being pushed now
 

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Has anyone reported any battery degradation on their Kona as yet?
Does the battery still appear to be operating at your expected level?
I'm at 15100 miles after 5 months of ownership and have not noticed any decrease in range.
 

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Thought I'd come back to this with a bit of maths.
Last night I did an 86% charge (14->100) putting in 58.2 kW which works out to 67kWh.
If we attempt to figure in some power lost in charging (7.2 out of the wall and the car was displaying 6.8 in) we get 54.9kW added or 63.8kWh.
Which is a long winded way of getting to no visible degradation after 20k :D
 

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I think its way simpler than that
1. Ideally drive from full to nearly empty (eg. 100% > 10%). So the total consumption is 90% in this case (Variable X)
2. Check your efficiency - lets say 3.4M/KWh (Variable Y)
3. Check the distance driven - lets say 200M (Variable Z)

Then your battery capacity should be: Z/(X*Y) = 200/(0.9*3.4) = 65.35KWh
 

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In some electric car forums it is believed that true battery capacity at start of life is possibly 10% higher than the manufacturers' specified value, but the SOC and SOH software is arranged to conceal this extra 10% and consequently it will only be after the actual capacity has dropped to below 100 % that any degradation will be apparent.

There is a very long thread about EV battery degradation here https://www.mykiasoulev.com/forum/viewtopic.php?f=6&t=434
 

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I wouldn't trust using distance and efficiency - there is too much variation in weather.
Having an internal buffer would make perfect sense for allowing for manufacturing variance and matches how phone batteries and solid-state harddrives wotk
 

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@MrChaz ,
I'm not quite sure what weather or other variances have to do with battery capacity. That method simply tells you how many KWh are in your battery (excluding any buffers manufacturers concealed or locked).
If you have bad weather then you have lower efficiency and either you drove less distance or you used more capacity. They go together hand in hand - you still get the same value.
 

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I recently got my hands on my wife's Kona for a decent drive. It is just about to tick over in to 30k miles, so seemed like a useful time to see if the battery was holding out OK.

I don't have access to any diagnostics, so this was only ever going to be a test based on data available within the car, so this might not be considered very scientific - so don't judge me.

I was initially surprised to see relatively low reported range on the GOM (202 miles at 89%), which made me concerned there had been a significant deg in battery. However, after a brief test, this appears to have been a combination of my wife's rather heavy right foot, the low air temperatures and possibly her recent decision to replace the front tyres with considerably more grippy Avons (which she tells me are far better in terms of traction than the Nexens).

On the recent drive (largely motorways, but peak period M25 reduced speed limits), with an early start in cold conditions (0-3 degrees C) I was able to get an average 4.0mi/kwh for the first leg and then on the return journey (in temperatures of 8-11 degrees C) I was able to get 4.5mi/kwh. On this overall roundtrip, I travelled 135 miles and the battery dropped from 89% at the start to 41% by the end. So 135 miles took 48% of the battery - which to me suggests 100% battery use, over the same profile trip, could have delivered around 280 miles? Accepting I may have got the maths wrong, but this felt much more like the car performing at roughly its as-new range - which was pleasing.

Frustratingly I failed to note the battery percentage at the turnaround point, so can only try to calculate the consumption over the total journey, which was showing as an average of 4.3mi/kwh for 135 trip. I think this means the car used 31.4kwh and led to a battery depletion of 48%. Factoring this up would give a 100% capacity of over 65kwh, which would be odd, as the battery is only supposed to have 64kwh of usable capacity. Clearly not a hugely accurate approach!

Despite not being an entirely accurate method of measuring battery capacity - the general feeling is that the battery is providing something approximately the same as the originally provided 64kwh of capacity. Now, whether this is because there has been no degradation over those 30k miles or the battery is degrading within a buffer is not something I can comment on - but regardless we are pleased to have a car with 30k miles on it that is seemingly able to perform in the same manner it did on day one. Unless my maths are completely all over the shot - in which case feel free to disappoint me!



John
 

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My understanding is that the buffer on the Kona is 4.7%... 64 kwh available of 67.1 kwh total. I would assume that until that buffer is used up, you won't see any degradation. It's unlikely at 30k miles.. The GoM varies from driver to driver.. My lowest 80% GoM range in 23400 miles was about 210 and my highest was over 280 miles. I just had a GoM 100% range of 339 miles 2 weeks ago at over 22000 miles. Right now, I'm hovering at around 250 miles range at 80% which translates to a little over 300 miles at 100%. I'm in Florida and don't use the heater at all. I do use the AC occasionally like today as we had 84F/29C today..
 

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@carima, your numbers look OK. 65kWh is not uncommon. It means that your battery is holding well!

If you want a bit more precise calculations you would need to drive from full to nearly empty (<10%). My understanding is that battery readings (remaining capacity) may get less accurate once battery start degrading. Eg. it may start dropping quicker at low SOC. Driving to low SOC eliminates assumption that SOC% is linear (it should be when battery is good) and shows more precise numbers.

But anyway, it looks like your battery is fine. Luckily no one reported any degradation so far so it is good prognostic for us all :)
 
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