Well 3,75V cannot be right, I think the cells are charged closer to 4V, not 3,75V.

 

Nominal voltage is typically about the midpoint between lowest and highest allowed voltages. See e.g. https://batteryuniversity.com/learn/article/confusion_with_voltages for more information.

Lähetetty minun FP2 laitteesta Tapatalkilla

 

And the quoted spec sheet gives Vmax as 4.15 volts (like Petteri suspected) and Vmin as 3.0 volts. These values seem pretty typical.

Lähetetty minun FP2 laitteesta Tapatalkilla

 

Yeah, I think folks here know that 43Ah cell datasheet pretty well. Two of them in parallel makes 86Ah, that's the 10% more than 86Ah.

The nominal voltage is not the full charge voltage. Batteries are analyzed in terms of their discharge curve: initially voltage drops very quickly when charge is extracted (Ah), then the curve is level in the middle, and then there is a knee and voltage drops very quickly again. The best part is the middle! The area below this curve is the energy yield of the battery (VxAh=Wh). The nominal voltage is such that if you extract x charge from a battery then Vnominal times that charge is the area below the charge curve. Think of it as a kind of average.

Because Li-Ion cells can be charged to 4.2V (and more) and the Ioniq only charges to 4.12-4.14V, there is your top buffer, for longevity. Because it discharges down to 3.0V (lowest cell) and more energy could be extacted, there is your safety buffer.

If you're planning for longevity. then the lowest you keep your average SoC, the better. Just charge the amount you're going to need plus a safety buffer.

 

No idea if it applies to EV batteries, but I vape (use e-cigarettes) and they use high performance Lithium Ion cells and they are always charged to 4.2v. At 3.7v most devices have a cut-off point as to not drain the battery to much and help prevent degradation. So your calculations at 3.75v is closer to empty, than full, at least regarding e-cig cells (Name brands: LG, Samsung, Panasonic etc).

 

Check out these posts: Battery usable Capacity and Safety Margins (Buffers), New battery layout and motor components in Hyundai / Kia Electric Vehicles. and my own post The BMS Plots, 3: discharge curves and battery capacity

 

Regarding longevity, a good, recent study points to the greater ageing factors being high Depth-of-Discharge and high State-of-Charge. That means that the more often you charge, the better, and the lower you keep your SoC, the better. Low state of charge is only harmful at levels near 0V, which never happens on an electric car.

Extending Battery Lifetime by Avoiding High SOC

 

Yes, thank you all for the replies. I will be looking at it all over the next few days. The service manual lists 2.5 to 4.3V/Cell (240 to 413 for the pack) as the battery voltage but does have some data sheets that hover indicate around 4.05V. max from the scanning software. It does list capacity at 28KW. I do see that most LiPo batteries charge at 4.2V. Aside from the specs that are slightly different, the battery curves should be similar to what the Ioniq has for a battery and I am happy to see the favorable data. I understand the new Ioniq (38 KW) and the Niro and Kona do not use LG batteries? Is that correct?

 

Wow! It’s a car, charge it, drive it. ?

 

That's what I have been doing! One thing I realized the other day, I had not been to a gas station in 21 days. Charging at home is so convenient. 2000 miles in 36 days. I truly love this car and enjoy every moment driving it. I regret not buying two! I just want to see about true battery capacity facts. I am a little late to the game as it came out in 2017 and I am new to the site.

 

Wow! Real data from the service manual! We didn't have that back then. Is there a link in this forum? 2.5 to 4.3V, there's your buffer. You'll never see it above 4.16V or below 3.0V.

 

I wonder if, as the cells age, the voltage range used will increase. So the user sees 28kWh useable for a very long time. Does anyone have cell or pack voltage at 100% displayed state-of-charge when new? Then we could compare with a 3-year old!

 

I have acquired the Hyundai factory battery service manual

Hi, could you share the source of the manual. I was looking for Ioniq EV service manual, but I only see manuals for HEV, not EV model.

 

Hyundai Service Website

www.hyundaitechinfo.com

Pay for a 1 week subscription and you can download (print to PDF) everything. I bought a 1 month as I have a Veloster too. 1 week would have been plenty. Electrical diagrams, awesome factory shop manual, TSBs, special service information, etc for any Hyundai vehicle. I suggest if you are planning for a 2020 you can get that as well. The 2020 data just posted 3-4 days ago. Just a lesson learned, it only fully works with Internet Explorer. Google Chrome will not print the graphics and diagrams correctly. I lost a day figuring that out. BTW I am sure this is for your own use and the docs cannot be shared publicly.

Enjoy! I love the data.

 

Hyundai Service Website

www.hyundaitechinfo.com

Pay for a 1 week subscription and you can download (print to PDF) everything.

Got it. It looks like there is some extra info on some procedures in TSBs as well. I would suggest to download all current TSBs as well as supplement to the service manual. Sure enough - the battery is fully serviceable, so not much worries for the future, even for cars without lifetime warranty for second owners.

Btw, there is battery calibration procedure in GDS to re-calibrate battery after repair.

 

As I only charge once a week, I would take my chances @ 80% after 2000 cycles in 38 years of use, just not sure I would last this long ;-)

@nburd Thanks for manual picture - finally revealing the thing I and many others were suspecting all alone. Yes, it uses only 5-95%(explains BMS vs. Display SOC discrepancies), so 5% bottom and 5% top buffers. And the battery is a tad more than nominal ~31.?kWh due to cells have a bit more capacity ~32-33kWh vs. nominal levels by the specs.

I know it is true as my L2 charger (Juicebox Pro 40) knows my car charger efficiency -92% and If I let it use default 28kWh, it would measure it and stop charging, so I have to modify default to 31kWh and 150 miles range to make it charge it to 100% and and provide more accurate added range figures.

 

I noticed there is a lot of confusion regarding basic units of electric power and energy among some EV owners. It’s a shame, since it’s their daily bread, if you will. There is use of all variations of upper and lower case of “k” and “w” to describe energy capacity of the battery, energy drawn to charge it, energy per mile consumed, etc., like KW, Kw, kW, or kw. While only one is valid as a physical unit (kW, kilowatt), it’s not even a unit of energy but of power.
Power is not energy. You can have an industrial electric heater rated at 28 kW. It will draw 28 kilowatts of power from the grid at any instant. Over 1 hour it will draw 28 kWh of energy from it, and that will be what you are going to be charged for. If you shut it down after 30 minutes, you will be charged only for 14 kWh. Your electric bill states energy consumption in kWh. You could have consumed that energy in 1 hour using the 28 kW industrial heater, or 280 hours using a 100 W light bulb.
Sorry for the rant, but please have the units right. You don’t measure gas/petrol at a gas station in horsepower. You pay for gallons/liters which have a certain amount of chemical energy, not power. Energy is equivalent to work. Power is work divided by time. You can have a guy dig a ditch in a week. It requires a certain amount of work. You can have the same work done by an excavator in 10 minutes. The excavator has much more power than the guy with a spade.

 

I see a lot of folks here and on the Web who state that the 28 KW Ioniq EV Battery has "extra capacity" built in to assist with longevity (you never charge to the real 100% capacity of the battery, which prolongs battery life). The Owners manual says to charge to 100% and recharge at 20% ideally. I have acquired the Hyundai factory battery service manual and it states the battery is rated 28 KW. It states it can provide 78 AH @ 360V (78A*360V=28080 W). It has 96 cells that are charged to 3.75V when charging. If I do the math, this totals only a 28 KW total capacity and no real extra. Also my charging data so far says At 100% I am putting in about 30 KW (minus charger losses equals 28 KW).

If there is extra capacity where would it come from? Charging to more than 3.75V?

It is assumed that Hyundai only publish "usable capacity" and not total capacity, so, that is all that you can find in Hyundai documentation i.e. 78 Ah is usable capacity of the cell-group and so on.
Battery consists of 192 cells BTW and not 96, these 192 cells are grouped in 96 groups in series, each group contains 2 cells in parallel.
It is believed (but not confirmed) that the total battery capacity is ~10% higher than the published usable. Indications for this you can find in the LG Chem document you have provided (if these are the cells used in the Ioniq):
1. 43 Ah cells - two in parallel makes it 86 Ah per group ~10% higher than the 78 Ah published.
2. "Electric power capacity" 161.25 Wh - 161.25x192 = 30960 Wh or 30.96 kWh, again ~10 more than the published 28 kWh.

 

Interesting, Hyundai does not indicate a total of 192 at all in the shop manual. Maybe it’s an error, here is a detail of the pack. 6 packs of 6 cells and 6 packs of 10 cells for 96 total cells.

 

It continuously amazes me how much people pick apart the battery capacity of a given EV. The range of fossil cars has been all over the map for a century versus their fuel tank size and nobody bats an eyelash. It varies, because physics, no matter what the power train.

 

Indeed it is 96s2p pack arranged in 6S and 10S modules, 2P means a parallel pair in battery talk: Kia Ioniq 24V 6s Battery Tested at 85Ah. ~2kWh.

You can clearly see - it is designed for real pass-through air cooling. There is a BMS and integrated heater (orange) connector for every module. It also seems to be possible to open the module to replace individual pairs. This is more economical than replacing a whole module: ~$900 6S$5 & ~$1200 10S new modules. You can see the recycled 6S module is $400, and $540 for Kia Ioniq 36V 10s Battery Tested at 85Ah ~3.1kWh. Not bad savings!
6x6S + 6x10S = 12.4 + 18.6 = 31kWh "nominal" capacity with 27.9kWh available (90%). This is nominal specs, in real life it may be 10% more with new cells.

 

Yes a very neat pack. I want to buy one and take it apart. See my recent new thread.......

 

Yes, and that's part of the fun of this forum as well...

 

Folks interested in 2020 EV battery info. Looks like it barely has any buffers 0-97 vs. 5-95 on 17-19 EV. Maybe because of it is water cooled Hyundai is comfortable with only 3 % top buffer:
2020 EV High Voltage Battery System

Item	Specifications	Remarks
Cell Configuration	88-cell	-
Rated Voltage (V)	220 - 378
Nominal Capacity (Ah)	120	-
Energy (kWh)	38.3	-
Weight (kg)	328.7	-
Cooling system	Water Cooled	-
SOC (%)	0 - 97	It can be checked via Diagnostic tool.
Cell Voltage (V)	2.5 - 4.3	It can be checked via Diagnostic tool.
Pack Voltage (V)	220 - 378	It can be checked via Diagnostic tool.
Voltage Deviation between Cells (mV)	40 or Below	It can be checked via Diagnostic tool.
Insulation Resistance (KΩ)	300 - 1000	It can be checked via Diagnostic tool.
Insulation Resistance (KΩ) [Actual Measurement]	2 or more	Megohm Tester

2019 EV High Voltage Battery System

Item	Specifications	Remarks
Cell Configuration	96-cell	-
Rated Voltage (V)	360	-
Nominal Capacity (Ah)	78	-
Energy (kWh)	28	-
Weight (kg)	271.8	-
Cooling system	Air Cooled Type	Forced Cooling of the Cooling Motor
SOC (%)	5 - 95	It can be checked via GDS.
Cell Voltage (V)	2.5 - 4.3	It can be checked via GDS.
Pack Voltage (V)	240 - 413	It can be checked via GDS.
Voltage Deviation between Cells (mV)	40 or Below	It can be checked via GDS.
Insulation Resistance (KΩ)	300 - 1000	It can be checked via GDS.
Insulation Resistance (KΩ) [Actual Measurement]	2 or more	Megohm Tester

 

Water-cooled or not - allowing the user to access a range of 97% compared to 90% can only lead to one thing - faster degradation. A 2020 owner should not routinely charge to 100% in my opinion- I hear the software now enables automatic charge stop at a reduced SOC.
I say this from experience owning a 2013 Leaf that had 88% reported health. It had been a demo car, and was probably left plugged in at 100% for extended periods.

 

I think this datasheet confirms my initial assumption that the cells used in the 38.3kWh Ioniq are NCM622 (identical to the Kona electric cells) arranged 88s2p. 60Ah per individual cell. Nominal voltage 3.63V per cell (in another datasheet they stated nominal voltage of 319.4V for the battery).
(Just-drive-it folks may skip this post...)

 

In 2021 I will be looking for a 'previously enjoyed' 2018 Ioniq EV.
Considering your experience with your present car would you trade up to the 2020 model just for the bigger battery?
?

 

How many times being charged to 100% SOC in one month is too many times? And what's the maximum amount of time it should be left at 100%?

 

Good questions, and all "how long is a piece of string" questions. Cell balancing is recommended about once a month, which requires charging to 100%. So I would say once a month and leave it at 100% for as little time as possible. When I charge mine to 100% either to balance the cells or before a long journey, it is overnight and drive the next morning.

What does everyone else do?