Why shouldn't I charge my 64 kWh Kona EV to 100% every day?

Discussion in 'Hyundai Kona Electric' started by JSU, Apr 10, 2019.

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  1. ajstjacques

    ajstjacques Member

    Not sure if that interest anyone, but I checked with my OBD scanner to see what 100% charge was and it looks like it's ~95% of the usuable capacity of the pack. Here is a screenshot of the torque app.

    Screenshot_20190413-202609_Torque.jpg
     
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  3. The battery is quoted in the VIN breakdown as "LiPB 356 V 180 Ah". Do you think that's accurate and might reflect the full capacity or the masked capacity?
     
    navguy12 and electriceddy like this.
  4. My understanding is that in Canada there are no legal definitions of "unlimited" or "lifetime" so any warantee must be defined. I haven't researched this at all but you might find that exclusions may make these warantees largely equivalent despite the way they are "headlined" in their respective countries. Also, consumer protections vary widely from market to market and warantees will reflect that. Hyundai will warrant as little as possible.
     
  5. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    My guess is that it's due to different laws (perhaps consumer protection laws?) in the U.S. vs. Canada.

    Right. The actual wording of the warranty will be written by lawyers, so the actual wording may be misleading to the layman... which is perhaps at least part of what lead Mattsburgh to make a wrong conclusion about what the warranty actually covers.

    The plain-language description by Hyundai, which I quoted above, is probably a better indicator to us non-lawyers of what the warranty actually covers.

     
  6. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    Thanks!

    This is for a Kona EV, then?
     
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  8. ajstjacques

    ajstjacques Member

    Yes, Canadian Utlimate version
     
  9. karma

    karma New Member

    What exactly does this mean in regards to degradation vs. failure? If in five years my capacity and range is diminished by 20% what will Hyundai do if anything? What if it's down 50%? This warranty is unclear to me and dealers are clueless. Guess I may have to call Hyundai and ask them.
     
  10. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    In theory, conventional wisdom says a BEV shouldn't fall to less than 70% of original capacity within the battery pack warranty period. But EV makers appear rather reluctant to specify an exact capacity at which they'll replace a pack for degradation. Hyundai failing to specify a lower limit to capacity, but guaranteeing replacement in case of "failure", apparently meaning complete failure, is IMHO fairly typical for auto makers.

    That doesn't necessarily mean that nobody will ever get a pack replaced under warranty for the capacity falling too low, but there might be some leeway for an authorized service department to make its own judgment about what constitutes excessive capacity loss.

    If I recall correctly, Nissan originally refused to guarantee a minimum capacity, but said they would replace the pack if the power level falls too far. Of course, power output in a BEV is limited by battery capacity, so the two are somewhat related. Fortunately -- again, if memory serves -- Nissan finally relented on that and now guarantees a minimum capacity.

    If you do get an official answer from Hyundai, Karma, I hope you'll report it here!
     
    Last edited: Apr 15, 2019
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  11. Some 2017 Bolts had replacement packs installed in warranty (including one owner near me) due to low level cell loss, some cells would prematurely fall below the minimum level at low soc causing premature turtle. This is probably the most common "defect" I have heard of. As far as capacity level,yet to be determined. The only proof would be a range test compared to new in the same conditions as the manufactures won't accept third party diagnostics info such as Leaf or Tesla spy and Torque pro.
     
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  13. Pushmi-Pullyu

    Pushmi-Pullyu Well-Known Member

    It's interesting to contrast discussions of (or arguments over) how very difficult it is for even a professional in the field to determine the actual capacity of a li-ion battery pack, versus claims by someone using a specialized meter such as Leaf Spy that they can measure the exact capacity. Well, since capacity varies at least slightly by temperature, I'd be skeptical that a (for example) Leaf Spy reading is all that accurate, unless the test was performed in temperature controlled conditions, which isn't likely for the average car owner.

    And altho I have no doubt that some or many legacy auto dealer service departments use the difficulty of measuring actual capacity to unfairly refuse to replace a battery pack under warranty -- you don't have to look far on Leaf discussion forums to see reports of that -- I do wonder just how they would precisely measure the current capacity of a li-ion battery pack even if they really did want to do that accurately.

    It's a thorny problem.
     
    Last edited: Apr 15, 2019
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  14. srkz

    srkz New Member

    Just wanted to clarify on the 2019 Kona Electric battery warranty - it's lifetime in the US but only for the first owner of the car.

    Page 13 of the US 2019 Owner's Handbook & Warranty Information states:

    "Hyundai Lifetime Hybrid Battery, Plug-in Hybrid Battery, and Electric Vehicle Battery Warranty - Original Owner (applies to Hybrid Battery, Plug-in Hybrid Battery, and Electric Vehicle Battery only). The original owner is defined as the first retail purchaser of the vehicle who took delivery of the vehicle on its date of first use. The warranty for the Hybrid Battery, Plug-in Hybrid Battery, and Electric Vehicle Battery shall remain in effect throughout the ownership period for the original owner."
    For subsequent owners, it's limited to 10 years or 100,000 miles.

    The warranty manual also does not clarify at all whether reduced capacity over time is considered normal wear and tear (not covered), or list any specific values for anything battery-related, so I suppose we'll just have to wait and see and hope that Hyundai handles it well if the situation ever comes up.

    The lack of detail and clarity in the warranty does make it seem a bit of an empty promise, though. Hopefully not, but only time will tell. Given how vague it is though I'm not sure how relevant it really is to the discussion of whether or not charging to 100% all the time is a good idea.
     
  15. I think they are trying to protect themselves against possible loopholes/fraud that the lawyers might conjure up down the road. It all depends on how well this battery holds up after 10 years. I am sure the odd exception won't be a problem for them, but they don't want to be ripped off either by greedy lawyers.
     
  16. It seems to me that if the owner's manual does not specifically say "don't charge to 100%" then it probably doesn't matter. No manufacturer is going to encourage behaviour that will get them into warrantee trouble in years to come. I don't recall any advice in the manual that specifies particular battery hygiene.
     
    Mike Vincent likes this.
  17. engnrng

    engnrng New Member

    I don’t read this forum to find out who “won” an argument.

    One of the reasons I chose the Kona (I am in US) is the lifetime battery warranty. I do understand now that the possibility of eventually getting a “free” replacement battery is tiny. The risk of the lifetime warranty cost to Hyundai in the general population is also tiny. The warranty only applies to original owners, it does not pass to new owners on resale. For my ownership, I anticipate 1 charge per week, having a 40 mile commute, even with side trips and errands, I will still be between 10% and 20% when I recharge on weekends. If one expects a degradation of 30% for 3000 20%-to-100% charge cycles (my dealer told me 70% was the warranty threshold), then I am looking at 3000 weeks of that use (and I will retire in less than 10 years anyway), which calculates out to over 50 years, assuming a few long trips along the way. Since I am in my 60’s, Hyundai risk in my case is negligible. If an owner uses 100 miles per day, 5 days per week, with a charge cycle every other day, call it 3 charges per week, Hyundai is still looking at around 20 years. I read a recent article that batteries will outlast the typical 10 to 15 year life of US vehicles. I believe it. Hyundai is pretty brilliant in marketing, I think. They have virtually no risk associated with offering a lifetime battery warranty. I have a friend with 250,000 miles in 5 years of ownership of a Model S, uses DCFC most of the time (after all, it is free for him), has seen 10% degradation so far. So, 50,000 miles per year, at 200 miles per charge, gives him about 250 charges per year. For his 5 years, means 1250 charges so far, he is not even half way to his battery 70% capacity life expectancy. His S is in great shape, but he is thinking of trading in for a newer model (as so many in the US do after 5 to 7 years), so even a lifetime battery warranty in his case would have cost Tesla $0. Going out to half a million miles, 10 years, Tesla would still be safe!

    Just charge it and enjoy the drive! Follow the manual advice. I am going to change my L2 charge max back to 100%, the default from Hyundai. Why add to any range anxiety, since the most important reason I bought the Kona was based on cost per mile of range!
     
    Last edited: May 26, 2019
  18. I've had my Kona EV now for about two weeks. I drive about 35 miles per day on my commute, plus another 30 or so on Saturday morning trips to the farmers market and local Costco. So, about 200 miles per week in normal driving (no airport trips, which are 110 miles RT - the airport also has free EV charging, if available). I've been plugging it in every night to take advantage of a super off-peak rate here with San Diego Gas & Electric that's in effect from midnight until 6:00 am. I'm also downloading my 15 minute data from SDG&E every afternoon for the previous day to look at the effects of 1) the new EV TOU rate; 2) L2 charging of my new Kona; and 3) a new 8 kWh Sonnen storage battery that's supposed to cover any usage from 4:00 pm until 9:00 pm when we have a super high summer on-peak rate (I also have a 5 kW PV system).

    One reason I charge every night is so that I can see interaction of these components on a regular daily cycle. After reading through this thread, I may switch to charging once a week on Saturday night (the super low rate lasts until 2:00 pm on weekends). I'll still have a regular schedule to look at, but the charge will all happen in one big "bolus" every week. Thanks to everybody here for the discussion. Not sure what to think about the 80% or 100% charge thing, but it doesn't really affect me too much due to my relatively small daily usage. My dashboard showed an estimated range of 301 miles this morning (298 yesterday). As an engineer all I can say is...the more data I have to look at, the better.
     
    Last edited: Jun 7, 2019
  19. Good to have cheap power; I lived and worked in Mira Mesa / Sorrento Vly as an engineer for 20 years before moving down here. I have no charging access where I park in a leased spot and have to rely on a public charger 1 block away, which costs $0.40 per unit for either AC or DC, my choice. After 6 months of ownership my preference now (based on generally understood Li-ion lifetime data by SoC ranges) is to keep it between 40% and 70-80%, unless I'm going on a trip where I will charge to 100%. The manual doesn't offer advice about SoC ranges as we all know, only mentioning to defer to AC charging when possible to maintain battery health and to charge to 100% if SoC drops below 20%.
    The one thing I can add to the conversation is that the expected maximum recommended '1C' continuous charging rate is 74kW (if I've done my calcs right, 60 A x 4.2 V x 294) and as our DC chargers are all 50kW, the 46 kW maximum I get is well under that 1C rate and so it doesn't concern me as being particularly detrimental. I don't like to be too precious, but the car cost me 75 grand and those dollars were just as hard to earn and save as they would have been working in the US. Amusingly, the Model 3 has just been made available this week and the Standard Range Plus is priced exactly the same as the Kona and eNiro. The one advantage of the Kona over the other two is that it has the reversible heat pump system. The Tesla has the advantage of the superb supercharger network (even on these islands) which are less expensive than most public chargers. The next town from me (150 km) has four superchargers and only one 50 kW unit for the rest of us EV drivers.
     
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  20. Before I leased the Kona EV I was driving a Ford Fusion Energi PHEV, which I just turned in after the three year lease ended. The original EV range was about 25 miles but I was only getting 18 or 19 after three years, about half of my daily commute. When I started driving it I would look for public charging stations but it seemed that, around here, they were charging $0.50 to $0.56 per kWh. At that rate it was cheaper for me just to run on gasoline, even at $4.00 per gallon, and a lot more convenient to charge at home with my L1 charger that came with the car. I knew of some free public chargers that I would take advantage of when I could (San Diego Airport, Walt Disney Concert Hall in LA are two of them).

    I was really surprised at the new SDG&E super off-peak rate, which makes it very cheap to charge the EV with the L2 charger I now have. At $0.09/kWh (about 1/3 what my average cost was before switching to the new tariff), if you assume 5 miles per kWh (I've been averaging about 5.3) and 40 mpg for an ICE car, that's equivalent to paying $0.72 per gallon. A no brainer.

    The MSRP for the Kona limited was about $42,000. There's still a $7,500 federal tax credit and a $2,500 California rebate. That reduces the cost here by almost 25%. I think that Tesla has used up their initial round of tax credit eligibility so that now you only get $3,750. That makes a big difference.
     
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  21. Well 356 x 180 = 64 KW so I am going to say it may represent the net available capacity/ virtual battery.
     
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  22. It would at 3.63 V per cell. I'm wary of calculating an exact kWh rating because it's entirely dependant on what average cell voltage you choose. At 3.7 we have 65.2 kWh for example. No doubt there is a real v.s. 'virtual' range of SoC as you say but I think it's quite irrelevant to us as consumers and possibly even Hyundai as a systems integrator. LG Chem have to meet the performance spec as a vendor to Hyundai and any over capacity is their ace up the sleeve ... if you see what I mean. The "40kWh" Kona battery is rated by Hyundai at 120 Ah so you can see that it has 2 cells in parallel.
     
  23. kona battery is 67 Kw in Hyundai we are charging only 64Kw to 100% 3Kw is left for protection only !!!!! Answer to all 100% = 64 Kw 3Kw is 20% that so simple.
     

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