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I don't have the time to read such a long response (similar to a first page newspaper article). There is no way to make you understand what I have said, and I will repeat again: of two batteries of similar chemistries, the one of higher capacity will always take longer to fully charge than than the smaller battery. Forget about the 20-80% capacity, and concentrate off the total capacity of the battery. An extended range EV (as the post powerful tesla automobiles) have higher capacity batteries than the standard EV's. If top-charging an extended-range EV to increase its drive mile range, lest say 250 miles, it takes a longer period of time than charging it to extend the drive range to 40 miles. 15-minute charge =200-mile drive range (fast charger), while a 5 minute charge using the same fast charger = 40 miles. Now if both batteries are large enough to charge for 15 minutes, then the charging time per range will be equal at a 200-mile range.
This is a matter of physics.
What you're saying is inaccurate. Stop spreading misinformation.
This *is* a matter of physics and apparently a part of it which you do not understand. You're not going to get close to understanding this if a message board post with five paragraphs and a few extra sentences simplified in layman's language make it too hard for you to understand. I also gave you a real world example of this where at a fast charger, the smaller battery pack capacity takes the same amount of time to charge from 10% to 80% state of charge as a larger capacity pack does to get from 10% to 80% state of charge. This means more capacity added in that time period and at a higher power level since covering that same state of charge in a larger capacity battery pack in the same time period means you added more capacity in that time period. This is very explicitly different from what you're saying. If you do not understand it, then at least stop spreading misinformation so you don't have other people misunderstanding this as well.
I think your garden hose and fluid containers analogy about one post earlier is a good illustration of your misunderstanding of this. You're talking about taking a garden hose to a 1 gallon jug versus a 5 gallon jug and that the second one will take longer to fill. What you've missing repeatedly here, and what I have been explicitly stating would in this analogy by the interface between the garden hose and the size of the opening of the jug from which you're refilling it. The larger capacity jug (corresponding to the larger capacity battery pack) has a correspondingly larger opening in which this analogy-to-electricity fluid can be put in than that of the smaller capacity jug (corresponding to the smaller capacity battery pack). If the rate at which the garden hose can discharge its analogy-to-electricity fluid is greater than either of the jugs can actually take at a time but the larger capacity "jug" can take in more than the smaller one, then it will fill both of them up from 10% to 80% at the same time because the amount each jug "opening" can take corresponds to its capacity. This *does* make the analogy complicated, but that you don't realize you're missing this entire component which was specifically what I was talking about means your posts just seem like non sequiturs as they miss the point being made entirely and points to perhaps you not understanding this field very well.
Last edited by OyCrumbler; 09-10-2023 at 08:52 PM..
Battery Size
As the hunt for range supremacy continues, the battery capacity of some EVs has ballooned to absurd levels. Others are targeting increased efficiency. This plays a massive role in charging time. Upsize our barrel to an 85-gallon unit. Even with a fire hose, it'll still take longer to fill than the smaller 55-gallon barrel. While a GMC Hummer EV is built on an architecture capable of 350-kW intake, filling its 212.7-kWh battery compared to the 112.0-kWh pack found in a Lucid Air Grand Touring requires exponentially more time, even if the charging rate is similar. The Lucid can travel over 40 percent further on a charge while having 100 kWh fewer in its battery pack than the Hummer. Efficiency, indeed.
No doubt someday manufacturers will settle on a single metric for expressing charge times. But for now, know that filling up an EV's battery still takes considerably longer than topping off a gas-powered car's fuel tank no matter how or where you do it.
That is a very basic introduction to EV charging and misses some pretty key parts though that makes sense given that it's a short basic introduction. It also completely skips over what was being discussed which is that with larger battery capacities generally comes faster charging rates. Again, this is why larger capacity battery packs can take the same amount of time charge from 10% to 80% state of charge than a smaller capacity battery pack even though that means a much greater power levels delivered and thus more kWh of energy delivered.
That is a very basic introduction to EV charging and misses some pretty key parts though that makes sense given that it's a short basic introduction. It also completely skips over what was being discussed which is that with larger battery capacities generally comes faster charging rates. Again, this is why larger capacity battery packs can take the same amount of time charge from 10% to 80% state of charge than a smaller capacity battery pack even though that means a much greater power levels delivered and thus more kWh of energy delivered.
There are numerous videos and articles about battery size and charging time. Your 20-80% state of charge on the road is interrelated to the drive range per mile. So if you are charging a Hummer's huge battery to attain a certain driving range, and the driver next to you charging his vehicle that has a smaller battery, to attain the same drive range as your Hummer, guess which one will charge faster? The Hummer in the video was charged for 18 minutes, and do you see what was the result in relation to the drive range/time? The batteries in extended-range vehicles are heavier than the ones in most common EV's, and add the gross weight of the vehicle. For example, the Hummer weights over 9,000 pounds, so it takes quite a longer time to charge. Carrying all the weight increases power consumption. It is the same for ICE vehicles that are heavy and with powerful engines. These consume more fuel than smaller vehicles, and have larger fuel tanks, which in turn take more time to fill.
I am trying to inform you, but it does not seem to work. Just imagine that the hummer has a big tank compared to a small EV
Quote:
How does battery size affect charging? https://www.edmunds.com/electric-car...r.html#battery
A larger battery will take longer to charge than a smaller battery, all else being equal. EV battery sizes today range from around 30 kWh to more than 200 kWh. To illustrate the impact of battery size on charging time, consider two EVs, both using Level 2 charging (more on that in the next section) at a rate of 9.6 kW, which is the best-case scenario for home chargers utilizing the common NEMA 14-50 wall outlet. One of our EVs has a usable battery capacity of 40 kWh, the other 80 kWh. Not surprisingly, double the battery size means double the charging time:
Usable battery capacity Level 2 charging time (9.6 kW)
40 kWh 4.5 hours from empty to full
80 kWh 9 hours from empty to full
I have no idea if you will believe the US government explaining the relationship of battery size and charging/discharging time, but I am trying quite hard to not misinform others in this forum: https://www.energy.gov/energysaver/ev-charging-times
Quote:
Battery Size
Lithium-ion battery capacity is measured in kWh (Kilowatt hours). The average capacity is around 40kWh, but some cars now have up to a 100 kWh capacity. Just as the size of a gasoline tank will impact how far you can drive on a full tank, the battery capacity of an EV will have a direct impact on how much electricity it can store and how much range it can offer, so the higher the kWh the better. But the more capacity of a battery, the longer it will take to charge, even to 80 percent.
There are numerous videos and articles about battery size and charging time. Your 20-80% state of charge on the road is interrelated to the drive range per mile. So if you are charging a Hummer's huge battery to attain a certain driving range, and the driver next to you charging his vehicle that has a smaller battery, to attain the same drive range as your Hummer, guess which one will charge faster? The Hummer in the video was charged for 18 minutes, and do you see what was the result in relation to the drive range/time? The batteries in extended-range vehicles are heavier than the ones in most common EV's, and add the gross weight of the vehicle. For example, the Hummer weights over 9,000 pounds, so it takes quite a longer time to charge. Carrying all the weight increases power consumption. It is the same for ICE vehicles that are heavy and with powerful engines. These consume more fuel than smaller vehicles, and have larger fuel tanks, which in turn take more time to fill.
I am trying to inform you, but it does not seem to work. Just imagine that the hummer has a big tank compared to a small EV
Quote:
Originally Posted by RayinAK
I have no idea if you will believe the US government explaining the relationship of battery size and charging/discharging time, but I am trying quite hard to not misinform others in this forum: https://www.energy.gov/energysaver/ev-charging-times
Where you are clear on and which is something no one is contesting is that if you have a charger that outputs less than what the battery packs can take, then the larger capacity battery packs will take longer to charge. That's not being argued against at all. On a 50 kW DC charger or an AC home charger, the Hyundai Ioniq 5 I used as an example will take longer to fully charge the larger capacity pack. That's what the links you've been posting are saying and that's already known. That's also not the point of contention at all.
In those examples, the limiting factor is the output of the charger itself or in the case of AC chargers like the ones used for home charging, potentially the inverter on the vehicles. However, many DC fast chargers deployed now actually have nominal maximum outputs that are *higher* than what the battery packs can take. In those DC fast charging examples, the Ioniq 5, for example, have different rates of charge (kW, e.g. power) corresponding to the capacity of the battery pack they have. The Ioniq 5 is a good clean example of this because the difference between the battery packs is how many battery cells, and the modules that the cells are in, the vehicle has rather than a change in battery cell chemistry or form factor. The individual modules / cells can all safely charge individually at about the same maximum rate with the same charging curve, so having many more modules / cells in a pack means that the pack overall can take in higher total rates of charge. This is why both the smaller 58 kWh and larger 72.6 kWh capacity battery packs charge from 10% state of charge to 80% state of charge within the same 18 minutes at a maximum 350 kW output charger which is higher than either battery pack can take despite the latter being a higher capacity battery pack. This is *specifically* what I've been saying the whole time and this part has been incredibly difficult for you to understand. This is even hinted at in the last link you posted from the US government:
Quote:
When car shopping consumers often overlook how much of a charge a vehicle can accept at once. Unlike filling a car's tank with gasoline, every EV accepts charges at different rates, and a vehicle’s maximum charge rate is static. So, it won’t save time by charging at a more powerful charging station. That is why it is important to carefully consider an EV’s charging capacity when purchasing an EV. For calculations, get the optimal charging time for the EV by dividing the battery capacity (measured in kWh) by the power rating of EV’s onboard charger, then adding 10% to the loss of power associated with charging it.
This is all inherent in the quote from the Edmunds link you posted where it states "A larger battery will take longer to charge than a smaller battery, all else being equal." That bold'd part is key to understanding this--it is not just a throwaway qualifier. A larger capacity battery pack using the same battery cells underlying it as a smaller battery pack is not going to have all else being equal because it will be able to charge at a higher maximum rate and its charging curve for the pack will generally be higher in correspondence with the total capacity of the battery pack. the 9.6 kW AC charger they used as an example would be a charger that is the limiting factor here and is nowhere near the maximum charging rate for either battery so that's why it will take longer for the larger capacity battery pack. Again, that is irrelevant to what I was posting and it is something that no one is contesting at all.
Someone please chime in and tell me they understand this, because it does not seem like that difficult of a concept to understand, yet explaining this has been apparently very unsuccessful so far. If there's someone here who does understand this, please give a go at explaining this to RayAK because perhaps there's a better way to help him understand this.
Last edited by OyCrumbler; 09-11-2023 at 10:19 AM..
Where you are clear on and which is something no one is contesting is that if you have a charger that outputs less than what the battery packs can take, then the larger capacity battery packs will take longer to charge. That's not being argued against at all. On a 50 kW DC charger or an AC home charger, the Hyundai Ioniq 5 I used as an example will take longer to fully charge the larger capacity pack. That's what the links you've been posting are saying and that's already known. That's also not the point of contention at all.
In those examples, the limiting factor is the output of the charger itself or in the case of AC chargers like the ones used for home charging, potentially the inverter on the vehicles. However, many DC fast chargers deployed now actually have nominal maximum outputs that are *higher* than what the battery packs can take. In those DC fast charging examples, the Ioniq 5, for example, have different rates of charge (kW, e.g. power) corresponding to the capacity of the battery pack they have. The Ioniq 5 is a good clean example of this because the difference between the battery packs is how many battery cells, and the modules that the cells are in, the vehicle has rather than a change in battery cell chemistry or form factor. The individual modules / cells can all safely charge individually at about the same maximum rate with the same charging curve, so having many more modules / cells in a pack means that the pack overall can take in higher total rates of charge. This is why both the smaller 58 kWh and larger 72.6 kWh capacity battery packs charge from 10% state of charge to 80% state of charge within the same 18 minutes at a maximum 350 kW output charger which is higher than either battery pack can take despite the latter being a higher capacity battery pack. This is *specifically* what I've been saying the whole time and this part has been incredibly difficult for you to understand. This is even hinted at in the last link you posted from the US government:
This is all inherent in the quote from the Edmunds link you posted where it states "A larger battery will take longer to charge than a smaller battery, all else being equal." That bold'd part is key to understanding this--it is not just a throwaway qualifier. A larger capacity battery pack using the same battery cells underlying it as a smaller battery pack is not going to have all else being equal because it will be able to charge at a higher maximum rate and its charging curve for the pack will generally be higher in correspondence with the total capacity of the battery pack. the 9.6 kW AC charger they used as an example would be a charger that is the limiting factor here and is nowhere near the maximum charging rate for either battery so that's why it will take longer for the larger capacity battery pack. Again, that is irrelevant to what I was posting and it is something that no one is contesting at all.
Someone please chime in and tell me they understand this, because it does not seem like that difficult of a concept to understand, yet explaining this has been apparently very unsuccessful so far. If there's someone here who does understand this, please give a go at explaining this to RayAK because perhaps there's a better way to help him understand this.
Battery Size
Lithium-ion battery capacity is measured in kWh (Kilowatt hours). The average capacity is around 40kWh, but some cars now have up to a 100 kWh capacity. Just as the size of a gasoline tank will impact how far you can drive on a full tank, the battery capacity of an EV will have a direct impact on how much electricity it can store and how much range it can offer, so the higher the kWh the better. But the more capacity of a battery, the longer it will take to charge, even to 80 percent.
Ignoring the more minute variables, the charging time of a vehicle comes down to a few primary factors:power source, the vehicle's charger capacity, and battery size.
Charging any type of electric vehicle for a 15-mile drive range is twice as fast as charging to for a 30-mile range. Try it with your 300-mile range vehicle when the battery is discharged: charge for a 50-mile range to make it home, versus a 100-mile range.
Charging any type of electric vehicle for a 15-mile drive range is twice as fast as charging to for a 30-mile range. Try it with your 300-mile range vehicle when the battery is discharged: charge for a 50-mile range to make it home, versus a 100-mile range.
Again, this is inaccurate. What you're talking about is when the output of the charger is the limiting factor, as in the vehicle can take in more power at a time but the charger cannot deliver more power, then the smaller capacity battery pack will charge up faster. That's obviously what those links have referred to. That's not what I was talking about at all.
The scenario I was talking about was max charging rates for the battery pack where the charger output is *not* the limiting factor. In that case, if the underlying cells and modules are essentially the same between two battery packs, one with larger capacity and one with smaller capacity, then when they are charging where the charger output is *not* the limiting factor, the two will essentially charge for the same amount of time to go from one state of charge to another (like 10% to 80%), but the larger capacity pack will have charged at a higher power level and added more energy and range during that time.
I *did* just show you a link to this with a vehicle that's using the same underlying battery cells, but with two different capacities. That was with the Ioniq 5.
Quote:
Long range battery Fast charging
In the long range battery version (72.6 kWh), IONIQ 5’s 800 V battery system offers the following charging times: 350 kW DC station: charging time 18 minutes from 10 to 80% range added from 5 minutes of charging: 111 km. 50 kW DC station: charging time 1 hour from 10 to 80% range added from 5 minutes of charging : 28 km
Standard range battery Fast charging
In the standard range battery version (58 kWh), IONIQ 5’s 800 V battery system offers the following charging times: 350 kW DC station: Charging time 18 minutes from 10 to 80% Range added from 5 minutes of charging: 88 km. 50 kW DC station: Charging time 43 min 30 s from 10 to 80% Range added from 5 minutes of charging: 27 km
At a 350 kW DC station where the charger output is *not* the limiting factor as it has a higher power output than either battery can take in, the larger capacity battery pack added 111 km of range in 5 minutes of charging while the smaller capacity battery pack added 88 km of charging. 111 km is greater than 88 km. This is an apples to apples comparison as teardowns of the Ioniq 5 battery packs have shown that the two different capacity battery packs use interchangeable battery modules with the smaller battery pack simply having blanks in parts where more battery modules would be. This is a real, existing vehicle currently in mass production exhibiting exactly what I said.
This in turn is related to the C-rate of batteries which is a measure of the rate at which a battery is discharged relative to its maximum capacity. The Ioniq 5's two battery packs are using the same battery chemistry and form factor. They have the same C-rate, but the larger capacity battery pack has a larger maximum capacity. As I stated clearly from the beginning, with other factors holding the same and a charger that is *not* the limiting factor, the larger capacity battery pack will have a higher max charge rate overall since it's the same C-rate for all the cells within either the larger or smaller capacity park, but there is a greater maximum capacity for the larger pack.
Last edited by OyCrumbler; 09-17-2023 at 10:37 PM..
Charge your Tesla car that has a battery nearly discharged, lest say 9% capacity, for a period of time to extend the drive to 50 miles(record the time). Then when the battery is nearly discharged-again around 9%, charge the battery using the same power dispenser, but this time to attain a range of 100 miles. Compare the times. Another example: suppose that your car allows for swappable batteries that are of the same chemistries, but different capacities, one with greater capacity than the other. In this case the large capacity one will take a longer period of time to charge than the smaller one, regardless if done at home, or a Tesla super charger. Regardless of how you feel about it, battery size is one of three primary variables in battery charging.
Charge your Tesla car that has a battery nearly discharged, lest say 9% capacity, for a period of time to extend the drive to 50 miles(record the time). Then when the battery is nearly discharged-again around 9%, charge the battery using the same power dispenser, but this time to attain a range of 100 miles. Compare the times. Another example: suppose that your car allows for swappable batteries that are of the same chemistries, but different capacities, one with greater capacity than the other. In this case the large capacity one will take a longer period of time to charge than the smaller one, regardless if done at home, or a Tesla super charger.Regardless of how you feel about it, battery size is one of three primary variables in battery charging.
The first part of what you said is correct, the second example I underlined is potentially inaccurate if you are using a charger that can have higher output than the smaller battery pack can take. That second part I underlined is essentially what the two battery size capacities of the Ioniq 5 are, and clearly the larger capacity battery takes the same amount of time to charge at the supercharger as the smaller one does.
I'm trying to figure out what about this is so difficult, but I don't want to explain this too much in detail lest you then just dismiss it as too long. Let's make a very simplified example with numbers arbitrarily made and easier to digest.
Let's say there are two battery packs, one small and one large and the underlying battery cells within them are the same chemistry and form factor--same type of cell. The small battery pack actually has fewer of these battery cells than the larger battery pack does. Let's just arbitrarily say the small one has 50 and the large one has 100 of them (these numbers are way off for how many there are in real life, but we're keeping it simple) and that each of the cells are 1 kWh of capacity each. Each of the individual battery cells in either pack can safely rapidly charge as quickly as any other one, and it takes fifteen minutes to go from 20% to 70% charged, so that's charging them by half or 0.5 kWh--or essentially at 2 kW maximum input. Putting in energy faster to these individual cells and it can get dangerous, any lower doesn't matter though and is perfectly fine, and the battery system when charging distributes energy roughly equally to all of the individual cells.
The smaller battery pack with 50 cells works out to 50 cells x 0.5 kWh charged each so it takes in 25 kWh in that fifteen minutes which works out to an average rate of 100 kW charging power for that time period.
The larger battery pack with 100 cells works out to 100 cells x 0.5 kWh charged each so it takes 50 kWh in that fifteen minutes which works out to an average rate of 200 kW for that time period.
At a fast charger (a supercharger in Tesla terms) that outputs 200 kW or higher, the larger capacity battery pack will take the same amount of time to add *double* the energy that the small battery pack does as the larger battery pack will be distributing the max charge rate possible for each individual cell to *more* cells. That is what superchargers can output with many able to do 250 kW or 350 kW. Your home charger generally outputs 11 kW or less, probably more like 6 or 7 kW. In that case, it's so low that it doesn't take advantage of the higher maximum charging rate that the larger capacity battery pack has since it's a rate below both the smaller and larger battery pack.
Hopefully that clears things up. This is also related to what I was saying earlier about not just power input, but also power output. Each of the individual cells that both battery packs use have a maximum safe output they can do. The larger battery pack by dint of having more individual cells each also has thus a larger combined possible maximum output. Now if the motors at the other end of this are the same for the larger and smaller battery pack and the max output of the battery packs exceed what the motors can do, then similarly to charging and charger output, the different battery packs don't make a difference in the maximum amount of power the system can output at once since it's constrained by what the motor can take.
Last edited by OyCrumbler; 09-19-2023 at 07:43 AM..
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