janusz Grabon
Member
I have Kona EV 2019 for 2.5 months in New York state in July I'M getting 320 Miles on single Charger level 2 with any problem with charging 100%!!!!!! I have to remain every one Kona have 67 Kw battery not 64 Kw.!!!
Why shouldn't I charge my 64 kWh Kona EV to 100% every day?
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apu
Well-Known Member
Just a point of correction on your math 3 KW difference between 67 and 64 is 4.5% not 20%
I appreciate you live in a different time zone but I am very dubious that your getting 320 miles in July. Also 2.5 months with regards to degradation is hardly worthy of an anecdotal representation, get back to us when you have at least 2.5 years of charging at 100%. Please provide before and after BMS SOC and SOH readings.
janusz Grabon
Member
apu
Well-Known Member
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Please refer to proper terminology when discussing battery statistics :
https://www.energylens.com/articles/kw-and-kwh
yawn
Yes, learning a new language is not easy.
Esprit1st
Well-Known Member
5% ... ;-)
However, nobody really knows exactly these numbers. And they are unconfirmed. We also don't know if the extra capacity is used at the top or the bottom of the battery (to protect it from deep discharge).
apu
Well-Known Member
I think your numbers would make sense assuming that there are 98 cells in the 64 kWh bank. I initially thought this to be true based on what info was available and then realized torque pro PID only reports 96 available cells. If you use 96 cells then the rated nominal capacity of each cell is 3.70( which is a typical nominal voltage for this type of cell) and the math would again imply an rated average capacity of 64 KWh. Which again I suspect is "net available" capacity but ultimately this all conjecture unless we have a LG employee on the forum that can speak up and clarify
Anyway I suspect the upper and lower portions of the buffer battery capacity are not actually more physical battery than the reported nominal 64 kWh but a capacity delineated by increased or decreased voltage states as directed by the BMS but yet again conjecture.
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eastpole
Active Member
I'm not sure it's totally nonsense. For example, I am the only one who knows whether I am evacuating my family tomorrow morning from a slow-moving natural disaster like flooding or a hurricane, in which case I'll charge to 100%. Or whether I am making a 50 km commute with a 400 km battery, in which case I hardly need 100% charge.
In Canada, a few people drive long (and variable) distances for work, but Statistics Canada says:
In 2016, 12.6 million Canadians reported that they commuted to work by car. For these commuters, the average duration of the commute was 24 minutes, and the median distance to work among those who had a usual workplace was 8.7 kilometres.
I'm not one to say "Eight years is enough!" and then drive in a way that will cripple the battery in that time frame... unless I actually need to. If someone is running a daily shuttle from Toronto to Sudbury, or Boston to NYC, they should have the option of charging to 100% and running down to 0%. But the flip side is, if I do a typical Canadian commute distance plus a grocery run, I should probably never (^^ but see natural disaster, above) put the battery in that state. The engineers designing the car don't know our plans, so they leave it up to us.
There are 98 cells, here is the fix (in green):I think your numbers would make sense assuming that there are 98 cells in the 64 kWh bank. I initially thought this to be true based on what info was available and then realized torque pro PID only reports 96 available cells. If you use 96 cells then the rated nominal capacity of each cell is 3.70( which is a typical nominal voltage for this type of cell) and the math would again imply an rated average capacity of 64 KWh. Which again I suspect is "net available" capacity but ultimately this all conjecture unless we have a LG employee on the forum that can speak up and clarify
https://github.com/JejuSoul/OBD-PID...mits/730419d68c8187089d52e390e911512109f89b41
apu
Well-Known Member
Ah, brilliant thank you for the correction and PID .
You're forgetting that there are charging losses involved so you're going to need more than 1 kWh from the grid to put 1 kWh into the battery. Exact figures will depend on the car and charging speed but I've seen losses as high as 15% on some other EVs. Have not seen anyone measure charging efficiency of the Kona.
KiwiME
Well-Known Member
The OBC alone is 91% at best, that's from Hyundai. I tried to measure battery efficiency last year by adding up all the AC power I was billed for in one month (I only use an ABB billable public charger and it was all 7.4 kW AC) and compare that with the sum of all energy consumption tabulated in "History" for the same month. The reason for using an entire month is to negate the error due to starting and ending SoCs being different. I have to assume the Kona is accurate in determining those consumption values but came up with 85%. Taking out OBC losses gives me 93% for just the battery. Next time I would use the cumulative dash reading near the odometer but I wasn't aware of it at the time.
popnfrresh
Member
For all the people into electricity, im surprised no one had mentioned owning a sense device. I didnt check mine when I charged last time. I try not to charge at home unless I need to.
https://sense.com
https://sense.com
janusz Grabon
Member
syntaxfx
Active Member
If you're really interested, this video explains why 80% is a good limit for everyday use.
Jeff Dahn is one of the most experienced and knowledgeable people on the planet when comes to Li-Ion batteries.
My take is that it's just fine to charge to 100% if you are going to use the energy immediately - and I mean that within a few minutes of hitting 100%, you'll start driving and keep driving until you get back down to about 80%. It doesn't matter if it's AC or DC charging because the BMS has an algorithm to reduce the charge rate as it gets closer and closer to 100%.
The aim is to lower the energy level to the point where the anode and cathode are not getting clogged with hardened electrolyte. Typically, that's under the 80% line.
Why should I care? Well, I spent years learning how to get the most out of my petrol and diesel cars and keep them in good condition. To me it makes sense to learn how to get the most out of this drive train.
Ed C
Active Member
Believe it or not, I watched that hour long video....
What Prof. Dahl is saying is that a higher SOC (ie. at 100%) over time is worse than a lower SOC. But the main problem with batteries going dead are the build up of impurities onto the negative electrodes. The build up of impurities are from parasitic reactions between the electrolytes with mainly the negative lead electrode. One of the worst things to your battery is hot temperature, which can accelerate the build up. He had examples of tests he ran to determine the Coulombic Efficiency (CE) between different EV batteries (Li Co oxide which are used in Teslas; Li Ni Mn Co (NMC) which are used in our Konas; a mixture of Li NMC and Li Fe oxide used in Bolts; and Li Fe oxide used in Leafs). Increase in temperatures starting at 40 to 60 degrees Celsius shows increased degradation to the batteries. Interestingly, Teslas Li Co oxide batteries are the best even at 60 degree Celsius temperatures. But with the addition of additives, it can greatly improve the CE of the battery life.
So the takeaway is to keep the battery as cool as possible, then secondly to keep the voltage as low as possible....meaning a lower SOC. That is going to be tough here in SoCal, especially in Inland Empire during the summer where it can get over 100 degrees Fahreheit (over 50 degree Celsius).
What Prof. Dahl is saying is that a higher SOC (ie. at 100%) over time is worse than a lower SOC. But the main problem with batteries going dead are the build up of impurities onto the negative electrodes. The build up of impurities are from parasitic reactions between the electrolytes with mainly the negative lead electrode. One of the worst things to your battery is hot temperature, which can accelerate the build up. He had examples of tests he ran to determine the Coulombic Efficiency (CE) between different EV batteries (Li Co oxide which are used in Teslas; Li Ni Mn Co (NMC) which are used in our Konas; a mixture of Li NMC and Li Fe oxide used in Bolts; and Li Fe oxide used in Leafs). Increase in temperatures starting at 40 to 60 degrees Celsius shows increased degradation to the batteries. Interestingly, Teslas Li Co oxide batteries are the best even at 60 degree Celsius temperatures. But with the addition of additives, it can greatly improve the CE of the battery life.
So the takeaway is to keep the battery as cool as possible, then secondly to keep the voltage as low as possible....meaning a lower SOC. That is going to be tough here in SoCal, especially in Inland Empire during the summer where it can get over 100 degrees Fahreheit (over 50 degree Celsius).
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Pushmi-Pullyu
Well-Known Member
I wouldn't worry about it. The Leaf is the only BEV with common reports of premature battery aging due to heat, and that's only because the Leaf until quite recently had no active battery thermal management system. Even now, the longer-ranged Leafs use only forced-air cooling. That might be adequate, since (if I understand correctly), the e-Golf also uses only forced-air cooling, and we haven't seen reports of premature aging in that BEV.
Any BEV with a liquid cooled battery will keep the battery pack within operating temperatures during use and during charging.