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Is it really a bad thing?

I reckon about 80% of my charging is done on a 50kwh DC charger. I've only done 3k miles at far though.

I've had 145kw for free this month so it's hard to say no! (still waiting for octopus to sort my meter so I can get the 5p rate at home)

Genuine harm being done do we think? Or nothing to worry about?

Anyone got big miles on their Niro and suffered battery issues?
 

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As long as you give it a proper full charge on AC once or twice a month to aid cell balancing (on most cars this doesn't fully take place on DC) then I don't see any problems really. The Niro should definitely be able to manage this especially since it sounds like you're only doing it in the short term and will be doing more home charging in future. Don't worry about damaging the battery.
 

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Is it really a bad thing?

I reckon about 80% of my charging is done on a 50kwh DC charger. I've only done 3k miles at far though.

I've had 145kw for free this month so it's hard to say no! (still waiting for octopus to sort my meter so I can get the 5p rate at home)

Genuine harm being done do we think? Or nothing to worry about?

Anyone got big miles on their Niro and suffered battery issues?
Does the handbook or warranty say don't rapid charge more than say 20 times a month?
No, then don't worry.
In any case 50kW into a 64kWh pack is a low C rate.
 

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Does the handbook or warranty say don't rapid charge more than say 20 times a month?
No, then don't worry.
The handbook does say "We recommend using AC charging for usual charging of the vehicle.", and also says "Battery performance and durability can deteriorate if the DC Charger is used constantly. Use of DC Charge should be minimized in order to help prolong high voltage battery life." Suitably vague enough to mean not very much and give plenty of wiggle room if somebody kicks up a fuss. No idea about the warranty, can't be bothered checking.
 

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From Kia.com

Caring for your battery

Just like ICE vehicles, EV vehicles and especially batteries don’t live forever – and their lifespan depends on the way they are treated. For example, your chosen method of charging will affect the battery’s ability to prolong or not high voltage and capacity range.

Many electric car manufacturers also provide warranties that cover the battery and all other components for a period of many years (click here to find out, for example, about Kia’s 7-Year Warranty).

And there are several other things you can do to get the maximum mileage from your battery pack:
Your battery’s capacity range is sensitive to extreme temperature. So make sure your EV isn’t left in overly hot or cold temperatures for too long. Some manufacturers, such as Kia, provide additional features such as Winter Mode – designed to improve range and durability in cold weather
Make sure the battery charge doesn’t run out completely. The most efficient range for charging is between 20% and 80% of the battery capacity
Make sure the battery isn’t charged too much or too often. DC Charging should be kept to a minimum to help prolong your high-voltage battery life
(Again, refer to your owner’s manual for specific guidelines here)

EV Lithium-Ion Polymer Battery
The Lithium-Ion Polymer Battery warranty covers a minimum capacity for a period is 84 months or 100,000 miles from the date of first registration, whichever comes first. This warranty covers repairs needed to return the battery capacity to at least 70% (65% for cars shipped after 01 August 2019) of the original battery capacity. Where possible, the original EV battery components will be repaired and will be returned to the vehicle. If unrepairable, the EV Battery will be replaced with either a new or remanufactured Lithium-Ion Polymer Battery.
 

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I would recommend to not go beyond 80% when fast charging if it is done frequently.
The new 4+ now support "fast" or at least "faster" AC charging, when using a public charge point (if you have the right cable!) or if you are fortunate enough to have a 3-phase supply at home.
So do the concerns about cell-balancing and not going over 80% state-of-charge if properly fast-charging (via a DC charger) - also apply if charging at 50kw via the AC plug?
Within the vehicle itself - there must at least be an AC-DC recitifier and probably some other electronic wizardry making the connection between the AC charger socket and the main battery. So I guess my underlying question is, what is it that actually achieves the cell-balancing when charging more slowly (eg overnight at home), that doesn't happen when charging as quickly as possible (at a public DC charger)? And is this "regulator" technology (if that is really what it is) only in use when charging via the AC charge socket?
 

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The new 4+ now support "fast" or at least "faster" AC charging, when using a public charge point (if you have the right cable!) or if you are fortunate enough to have a 3-phase supply at home.
So do the concerns about cell-balancing and not going over 80% state-of-charge if properly fast-charging (via a DC charger) - also apply if charging at 50kw via the AC plug?
Within the vehicle itself - there must at least be an AC-DC recitifier and probably some other electronic wizardry making the connection between the AC charger socket and the main battery. So I guess my underlying question is, what is it that actually achieves the cell-balancing when charging more slowly (eg overnight at home), that doesn't happen when charging as quickly as possible (at a public DC charger)? And is this "regulator" technology (if that is really what it is) only in use when charging via the AC charge socket?
If you're top-balancing you can only do it when the battery is very nearly full, and your balance shunts or bleeders can only move a tiny amount of current, so it takes a long time. I certainly see my Leaf sometimes draw then less than a kilowatt for an hour or so when it's balancing. You wouldn't ever do this at a rapid charger, you've disconnected and driven off at 80% charge, you're not sitting round for an hour longer AFTER it's got to 97% already.
 

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So I guess my underlying question is, what is it that actually achieves the cell-balancing when charging more slowly (eg overnight at home), that doesn't happen when charging as quickly as possible (at a public DC charger)?
I've not worked on EVs, but cell balancing in the battery operated systems that I've worked on is slow, so by it's very nature, if you're trying to do a quick "zap and dash", there just isn't enough time to properly balance everything. Imagine you have 100 buckets that have random amounts of water in them - how long would it take you to get the same amount of water in each bucket? The BMS will work quicker than a person with a cup, but fundamentally, it's still a slow process of sloshing stuff around between different containers.
 

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The new 4+ now support "fast" or at least "faster" AC charging, when using a public charge point (if you have the right cable!) or if you are fortunate enough to have a 3-phase supply at home.
So do the concerns about cell-balancing and not going over 80% state-of-charge if properly fast-charging (via a DC charger) - also apply if charging at 50kw via the AC plug?
Within the vehicle itself - there must at least be an AC-DC recitifier and probably some other electronic wizardry making the connection between the AC charger socket and the main battery. So I guess my underlying question is, what is it that actually achieves the cell-balancing when charging more slowly (eg overnight at home), that doesn't happen when charging as quickly as possible (at a public DC charger)? And is this "regulator" technology (if that is really what it is) only in use when charging via the AC charge socket?
As said above, AC charging is limited to 11 kW on the e-Niro. Cell balancing is achieved by trickle charging the cells once they are close to 100%. Cells that are ´full´(ie the max voltage level is reached) will no longer receive charge, whereas cells that still accept current will continue to be slowly charged. Each cell has a slightly different chemistry so if you never charge to 100%, they will start to deviate in charge level. Consequently the BMS will not be able to properly estimate the charge level of the enire battery so it may report erroneous number. With large imbalances, some cells may reach close to zero charge when other cells are still at maybe 10% or more. In such cases the BMS protection will shut the entire battery down to prevent damage even though the GOM would indicate 40 km DTE.

I have no idea why it is not possible to balance when DC charging.
 

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I've not worked on EVs, but cell balancing in the battery operated systems that I've worked on is slow, so by it's very nature, if you're trying to do a quick "zap and dash", there just isn't enough time to properly balance everything. Imagine you have 100 buckets that have random amounts of water in them - how long would it take you to get the same amount of water in each bucket? The BMS will work quicker than a person with a cup, but fundamentally, it's still a slow process of sloshing stuff around between different containers.
Thanks for this.
Makes we wonder whether "Cell-balancing" really is by each individual lithium "cell", or just by blocks of cells that are hard-wired in series within the battery pack itself?
I imagine the discharge of the battery pack (ie using it whilst driving) requires some kind of series/parallel configuration to give the required high voltage and current ratings at the battery pack terminals prior to inversion for the drive motor(s). So charging the battery pack via its terminals whether by 240v per phase AC prior to rectification or by rapidly charging the battery pack at 415v(???) DC will similarly have to be via some kind of series / parallel arrangement within the battery pack itself. Trickle-charging the battery pack (via its terminals) only serves to keep its overall voltage slightly above nominal, whilst the individual cells internal chemisty sort themselves out. Trickle charging hundreds of individual cells would require an additional and pretty fancy wiring loom within the battery pack itself, to identify and then to provide the top-up charge that each individual cell needs. Some kind of low current digital bus maybe ?
Give or take the inevitable secrecy around individual manufacturers designs, I suppose I should try Googling the question to get past some of the overly simplistic / misleading explanations to try and get a better understanding of what's really going on in the control electronics around the new generation of on-board chargers.... Or have you already looked into this?
 

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Thanks for this.
Makes we wonder whether "Cell-balancing" really is by each individual lithium "cell", or just by blocks of cells that are hard-wired in series within the battery pack itself?
I imagine the discharge of the battery pack (ie using it whilst driving) requires some kind of series/parallel configuration to give the required high voltage and current ratings at the battery pack terminals prior to inversion for the drive motor(s). So charging the battery pack via its terminals whether by 240v per phase AC prior to rectification or by rapidly charging the battery pack at 415v(???) DC will similarly have to be via some kind of series / parallel arrangement within the battery pack itself. Trickle-charging the battery pack (via its terminals) only serves to keep its overall voltage slightly above nominal, whilst the individual cells internal chemisty sort themselves out. Trickle charging hundreds of individual cells would require an additional and pretty fancy wiring loom within the battery pack itself, to identify and then to provide the top-up charge that each individual cell needs. Some kind of low current digital bus maybe ?
Give or take the inevitable secrecy around individual manufacturers designs, I suppose I should try Googling the question to get past some of the overly simplistic / misleading explanations to try and get a better understanding of what's really going on in the control electronics around the new generation of on-board chargers.... Or have you already looked into this?
Trying to be nice about this post...yes you do need to look at some actual battery configurations.
 

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I've not worked on EVs, but cell balancing in the battery operated systems that I've worked on is slow, so by it's very nature, if you're trying to do a quick "zap and dash", there just isn't enough time to properly balance everything. Imagine you have 100 buckets that have random amounts of water in them - how long would it take you to get the same amount of water in each bucket? The BMS will work quicker than a person with a cup, but fundamentally, it's still a slow process of sloshing stuff around between different containers.
I have just an automated self-levelling system connecting up the water butts in my garden. All it takes are relatively small-bore pipes connecting up the bottoms of the water butts, with larger bore pipes just used for collecting the rainwater and pumping it out for use... But this analogy gets a bit more tricky given the shear number of individual cells in the battery-pack of a modern, long-range BEV
 

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Sincere apologies for the offense caused ... I'll willingly do my own homework on this....
No offense whatsoever. Everyone is learning about this stuff.
For your own car, the battery cells are hardwired in parallel and series to get the correct capacity and voltage. There is no switching within the pack for either charging or discharging. Ignoring the micro circuits for cell monitoring and balancing , all electrical connections between the cells are fixed.
 

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I have just an automated self-levelling system connecting up the water butts in my garden. All it takes are relatively small-bore pipes connecting up the bottoms of the water butts, with larger bore pipes just used for collecting the rainwater and pumping it out for use... But this analogy gets a bit more tricky given the shear number of individual cells in the battery-pack of a modern, long-range BEV
Nice analogy in a way
 

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The things I've worked on (which are admittedly a much smaller number of cells) have them wired in series for voltage, then parallel for capacity, but each cell is monitored and managed separately. I don't know they'd do this on something as big as an EV battery, but they probably have a much bigger budget to play with than I do, so I don't see why they wouldn't unless they were feeling lazy.
I have just an automated self-levelling system connecting up the water butts in my garden. All it takes are relatively small-bore pipes connecting up the bottoms of the water butts, with larger bore pipes just used for collecting the rainwater and pumping it out for use... But this analogy gets a bit more tricky given the shear number of individual cells in the battery-pack of a modern, long-range BEV
Water butts are a bit different, because you can fill from the top as you drain from the bottom, so the processes can happen in parallel, and a bottom drain has gravity to assist you. A battery cell is either charging or discharging depending on what you do to it (no gravity assist available...), so an analogy would be more akin to the old 5 litre/3 litre bucket challenge, which admittedly is a majorly flawed analogy in it's own way. The gravity thing also gives you an unfair advantage, so imagine if your water butts were stacked one on top of the other, rather than sitting all at the same level, and your system will no longer self level - that'd be closer to wiring cells in series.
 

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A few general points of interest here.....
There are 98 banks of cells wired in series.
Each bank is three 60Ah cells connected in parallel.
Each and every individual bank Voltage is carefully monitored by the BMS.
No cell/bank must be ever allowed to rise above a defined maximum of typically 4.2V.
Nor will any cell ever be allowed to over discharge below a certain point, perhaps 2.5V? (To prevent cell damage the car will stop if/when this super low SOC on any cell is reached)
The charging from 230V AC will use a boost SMPS converter to get the required ~411 Volts.
The cell balancing will perhaps be a ladder of resistors that can be switched individually or together as needed across any of the cell banks during the charging process in order to slightly reduce the charge current entering that individual cell bank. This process can dramatically slow down the time taken to achieve a full SOC, if a lot of imbalance is present. (I have not seen the schematic details for this car but this is the usual practice typically. They may have done something even more advanced and energy efficient with clever modern power switching techniques??)

The long established method of balancing the cells of Lead Acid and Nickel chemistry batteries by simply overcharging the whole battery absolutely cannot be used for Lithium Ion cells, as any over Voltage of any cell(s) would be disastrous. Some battery chemistries can accept slight to moderate overcharge, but not these.

Peter
 

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Are EVs only using passive rebalancing? Stuff I work on is moving to active switched cap based. More complex, but better efficiency. But this is smaller scale. Should scale up to EV sized battery packs, but don't know if they've bothered doing it.
 
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