You think it's a big step-up from 25W to 45W charging? - You might be wrong!

[wanderingfool2]

32 minutes ago, Curufinwe_wins said:

But 11W charging on a phone that is turned on is not 2x faster than 5W. It is more like 3-5x faster (in fact, while screen on, many modern devices don't charge at all on a 5W trickle brick)

With screen on, yea the idle consumption might be roughly neutral (at least on the phones I've used before).

 

The youtube video I posted earlier which used an iPhone 12 (so about a year and 3 month old phone) which used a 5w, 10w, and 20w actually had the 5w charge from 15% to 99% in 161m, with 10w in 117m.  Which is only 27% faster (1.37x faster)

 

I'm all for calling out marketing claims that are false, but really there isn't much to be said here.

 

2 hours ago, HenrySalayne said:

Ah, the good ol' cherrypicking results.

It is the numbers that are front and center in your first post.  So yea, not cherry picking results.  You also ignored that their S22+ numbers were only 1 min difference, and the "65w" that had a 4% lead at the 30 min mark ended up 3 min slower than the 45w to their test.  So yea, their data is flawed.  [Given everyone else at the 30 min mark was 7-9%].  It's foolish to say otherwise

[mr moose]

10 hours ago, HenrySalayne said:

Yes, but that wasn't the point here. The energy stored in the cell is proportional to the integration of the power over time. And there are power limits changing with charge state.

If we charge a battery with 5 W for 1 hour, the battery will be charged to 5 Wh.(ignoring losses). If we charge the same battery (and just assume the battery can take this) with 10W for 1 hour, it will be charged to 10 Wh.

 

That's not how charging lithium works though.   Forget what wattage the charger can provide,  for the bulk of the initial charge the charger is in constant current mode, which means the power delivered to the battery slowly increases.    You don't simply put X wattage into a battery.

 

[Curufinwe_wins]

52 minutes ago, wanderingfool2 said:

With screen on, yea the idle consumption might be roughly neutral (at least on the phones I've used before).

 

The youtube video I posted earlier which used an iPhone 12 (so about a year and 3 month old phone) which used a 5w, 10w, and 20w actually had the 5w charge from 15% to 99% in 161m, with 10w in 117m.  Which is only 27% faster (1.37x faster)

 

I'm all for calling out marketing claims that are false, but really there isn't much to be said here.

 

For sure, once you get above ~80% the differences got to be quite minimal, but that's also a bit misleading IMO in that real world charging speed doesn't matter if you have enough time to make it to 90+% in any metric. The only time it actually matters (and this is true for cars as well honestly, I drive a Model Y LR) is when you need quick charging which means your time is best spent sitting in that 10-80% window.

 

I think one of the mapped results was around almost 2xt faster for screen off up to 10W on iPhone 8 up to 80% and then heavy HEAVY diminishing returns for anything past that. (edit yeah, ~70min to 80 vs 130min. But see the note below)

 

Notice though this is with basically everything turned off. The more that runs in the background, the wider the delta until thermal constraints (or max IC) are reached.

 

I am *not* of the opinion this is a big deal. As mentioned previously, I only *really* care if companies claim say... 2x faster charging but then the charging speed is not faster. Just saying it supports a given charging wattage is so vague/useless a metric at all levels, I can't help but **shrug**

16 minutes ago, mr moose said:

 

That's not how charging lithium works though.   Forget what wattage the charger can provide,  for the bulk of the initial charge the charger is in constant current mode, which means the power delivered to the battery slowly increases.    You don't simply put X wattage into a battery.

 

This 100%. I forgot to mention that, was mainly thinking about the reasons *why this is* and less about talking about it directly. Also one of the reasons that as charging has gotten faster than the old 11W standard, voltages have generally moved to 9/12V (or higher) from 5V.

[HenrySalayne]

9 hours ago, Curufinwe_wins said:

This 100%. I forgot to mention that, was mainly thinking about the reasons *why this is* and less about talking about it directly. Also one of the reasons that as charging has gotten faster than the old 11W standard, voltages have generally moved to 9/12V (or higher) from 5V.

But just to circumvent the bottleneck of cables and plugs. The batteries themselves are still charged with the same voltage but much higher current. Step-down converters in the phone will take care of this.

 

10 hours ago, mr moose said:

That's not how charging lithium works though.   Forget what wattage the charger can provide,  for the bulk of the initial charge the charger is in constant current mode, which means the power delivered to the battery slowly increases.    You don't simply put X wattage into a battery.

With constant current the series resistance of the cell defines the power. The series resistance actually gets smaller with higher battery levels resulting in a reduction in power. So the power should naturally decrease the "fuller" the battery gets.

https://www.mdpi.com/1996-1073/10/9/1284

 

 

[mr moose]

34 minutes ago, HenrySalayne said:

But just to circumvent the bottleneck of cables and plugs. The batteries themselves are still charged with the same voltage but much higher current. Step-down converters in the phone will take care of this.

 

With constant current the series resistance of the cell defines the power. The series resistance actually gets smaller with higher battery levels resulting in a reduction in power. So the power should naturally decrease the "fuller" the battery gets.

https://www.mdpi.com/1996-1073/10/9/1284

 

 

Might I suggest actually learning how these things work before posting.  Check any charge graph you like.  The voltage applied to the cell increases during the CC stage of charging, Without doing this you will A: never have a CC stage and B: will at best take forever to charge the cell or at worst damage the cell.  Then after the cell hits saturation the charge method is swapped to constant voltage where a voltage of 4.2V is applied, during this mode the current flow will solely decrease as the internal resistance starts to rise.   In more laymen's terms,  the voltage is variable so the current is constant (and thus the power delivered increases over time) in order to protect the cell from damage.

 

 

 

 

If you look at the battery voltage, it is not linear.  You can also check the charge current and charge voltage for any given stage of the batteries charge cycle and see that the power delivered to the battery is not linear.  It essentially rises (during the majority of the charge cycle in CC mode) then drops. 

 

 

Graphs stolen randomly from across the net to show general trend for lithium cells.

 

 

[HenrySalayne]

3 minutes ago, mr moose said:

Might I suggest actually learning how these things work before posting.  Check any charge graph you like.  The voltage applied to the cell increases during the CC stage of charging, Without doing this you will A: never have a CC stage and B: will at best take forever to charge the cell or at worst damage the cell.  Then after the cell hits saturation the charge method is swapped to constant voltage where a voltage of 4.2V is applied, during this mode the current flow will solely decrease as the internal resistance continues to rise.   In more laymen's terms,  the voltage is variable so the current is constant (and thus the power delivered increases over time) in order to protect the cell from damage.

The charging power is not the charging voltage times the current, it's (charging voltage minus cell voltage) times the current. The current is defined by this deltaU and the series resistance of the cell. Irf you're charging with constant current, power is a function of the internal resistance of the battery (P = I² * R_i(SoC)) and so is deltaU.

 

16 minutes ago, mr moose said:

If you look at the battery voltage, it is not linear.  You can also check the charge current and charge voltage for any given stage of the batteries charge cycle and see that the power delivered to the battery is not linear.  It essentially rises (during the majority of the charge cycle in CC mode) then drops. 

 

For the early stages of charging (ignoring any thermal limits), the series resistance of the cell is almost linear, so deltaU is almost constant. That's why the charging curve is almost linear (power stored in the cells).

10 hours ago, Curufinwe_wins said:

 

 

 

[mr moose]

Just now, HenrySalayne said:

The charging power is not the charging voltage times the current, it's (charging voltage minus cell voltage) times the current. The current is defined by this deltaU and the series resistance of the cell. Irf you're charging with constant current, power is a function of the internal resistance of the battery (P = I² * R_i(SoC)) and so is deltaU.

 

For the early stages of charging (ignoring any thermal limits), the series resistance of the cell is almost linear, so deltaU is almost constant. That's why the charging curve is almost linear (power stored in the cells).

 

 

Huh?  It's the same equation, you are just calculating power from the current and resistance values instead of the voltage value.  Which if you do for any given state of the battery you will see it changes.     Ergo if you do not increase the voltage during the CC stage, you will not increase the charge in the cell.

 

The chargers output voltage will match the cells voltage while they are connected.  Here's another graph:

You'll note that the charge float voltage and the cell voltage are the same line (red). the blue line is the charge current (determined by the cell size).  The only way the black line (SoC) can increase is if the charge voltage increases during the CC stage (which it clearly does). 

 

[HenrySalayne]

50 minutes ago, mr moose said:

Huh?  It's the same equation, you are just calculating power from the current and resistance values instead of the voltage value.  Which if you do for any given state of the battery you will see it changes.     Ergo if you do not increase the voltage during the CC stage, you will not increase the charge in the cell.

 

The chargers output voltage will match the cells voltage while they are connected.  Here's another graph:

You'll note that the charge float voltage and the cell voltage are the same line (red). the blue line is the charge current (determined by the cell size).  The only way the black line (SoC) can increase is if the charge voltage increases during the CC stage (which it clearly does). 

No, this is a misconception. While a cell is charged its voltage must be equal to the external voltage applied by the charger (Kirchhoff's 2nd law). That is what we can see in these pictures. But that is not the same voltage as the internal voltage of the cell. And only the difference between the charging voltage and the internal voltage is doing work here. Maybe an example will make this clearer:

We have a battery with a cell voltage (currently) of 3V and an R_i of 1 Ohm. We want to charge it with 1 A of current. So we need 1 V (U = Ri * I) to charge this battery with 1 A.

But if we now apply 1 V to this battery, we would actually drain the battery. Is has to be a voltage of 4 V (deltaU = 1 V) to charge this battery with 1 A.

 

Here is a graph of the Ri of different batteries (taking from the doc in my previous post).

 

If we now charge these batteries with a constant current, power is calculated by P = I²* Ri. Because our current I is constant, P is proportional to Ri and will drop with the state of charge of the battery.

 

And we can clearly see this behaviour in this graph:

 

As we know from the infamous equation E = P * t, power is the derivative d/dt E. (thankfully nobody completely cra**** all over this equation )

So the steeper the curve, the more power is flowing into the battery. And as we can see, the curve is ever so slightly getting flatter the "fuller" the battery gets. Maths - great stuff!

 

[Elijah Kamski]

On 2/24/2022 at 12:37 AM, HenrySalayne said:

Even worse, neither the S22+ nor the S22 Ultra come with a charger.

Forget the children, think of the environment, then think of how the environment impacts children, in the end of it all, think of the children!

We need to ensure our company, Samsung, is making a positive impact to our children's future, by ensuring that the environment they'll have in the future is preserved. We do this by reducing e-Waste, specifically by removing chargers as everyone has one of those already, right?

Now, in terms of the 25W charger being no different than the 45W charger, and all of you saying that we're just trying to find a way to create money, there is a difference...

In our wallets, have you seen how fat our wallet's are getting?

In terms of benefits to the consumer, you can brag of having a 4 instead of a 2.

Samsung - Think different, but keep following Apple

 

[Heliian]

My Huawei blows these numbers out of the water.  My Samsung was great but nowhere as fast.

 

The Huawei only supercharges on its own block and cable.  It is a data cable, good quality. 

[mr moose]

15 hours ago, HenrySalayne said:

No, this is a misconception. While a cell is charged its voltage must be equal to the external voltage applied by the charger (Kirchhoff's 2nd law). That is what we can see in these pictures. But that is not the same voltage as the internal voltage of the cell. And only the difference between the charging voltage and the internal voltage is doing work here. Maybe an example will make this clearer:

We have a battery with a cell voltage (currently) of 3V and an R_i of 1 Ohm. We want to charge it with 1 A of current. So we need 1 V (U = Ri * I) to charge this battery with 1 A.

But if we now apply 1 V to this battery, we would actually drain the battery. Is has to be a voltage of 4 V (deltaU = 1 V) to charge this battery with 1 A.

 

Here is a graph of the Ri of different batteries (taking from the doc in my previous post).

 

If we now charge these batteries with a constant current, power is calculated by P = I²* Ri. Because our current I is constant, P is proportional to Ri and will drop with the state of charge of the battery.

 

And we can clearly see this behaviour in this graph:

 

As we know from the infamous equation E = P * t, power is the derivative d/dt E. (thankfully nobody completely cra**** all over this equation )

So the steeper the curve, the more power is flowing into the battery. And as we can see, the curve is ever so slightly getting flatter the "fuller" the battery gets. Maths - great stuff!

 

 

You are completely ignoring that the resistance in the cell and the voltage changes.  Power would remain the same only if current AND resistance remain the same,  as soon as you change one you change the power.    You have 4 values (current, voltage, resistance and power), If you fix two of those values you fix the other two values. 

 

 

 

 

[HenrySalayne]

3 hours ago, mr moose said:

You are completely ignoring that the resistance in the cell and the voltage changes.  Power would remain the same only if current AND resistance remain the same,  as soon as you change one you change the power.    You have 4 values (current, voltage, resistance and power), If you fix two of those values you fix the other two values. 

Did you read the graph right?

Ri doesn't change as much as you might think because they scaled the ordinate to reasonable values for better readability. At 10% Ri is around 38.5 mOhm, at 60% it dropped to 36.5 mOhm. That's only a difference of 5% and that's how much the power would change with constant current. If you start with 10W at 10% you would get 9.5W at 60%.

And once gain, that's exactly what we see in this picture.Almost linear at the beginning with minimal changes up to 70%.

[mr moose]

31 minutes ago, HenrySalayne said:

Did you read the graph right?

Dude I posted several exactly the same, I even pointed how it looks linear in my first post.  Did you read my post where I said that? You tried to claim the resistance changed with SoC now you are trying to claim it doesn't, I'm over this conversation, you are misinterpreting how the system works, misinterpreting how to use Ohms law for said application and most importantly you are ignoring the very NON-Linear charge curve of the cell.     

 

You don't need to be an engineer to see that the curve is non linear.  You also don't need to be an engineer to see that if the current is constant and the voltage increases (because of the source providing it) then the power also MUST increase.  The state of charge can remain somewhat linear during the CC stage but the power the cell absorbs maintaining that vector is increasing over time (i.e not linear).

 

Feel free to say what every you like about it, I'm just glad people designing a lithium BCM aren't going to be reading this and instead will be at stackexchange or eevblog forums.

 

 

[HenrySalayne]

51 minutes ago, mr moose said:

You don't need to be an engineer to see that the curve is non linear.  You also don't need to be an engineer to see that if the current is constant and the voltage increases (because of the source providing it) then the power also MUST increase.  The state of charge can remain somewhat linear during the CC stage but the power the cell absorbs maintaining that vector is increasing over time (i.e not linear).

I strongly suggest you consult an engineer in this case. The total voltage doesn't matter, only the difference in voltage between the cell and the external source is doing work. And as you charge up the battery, it's internal voltage will rise. So what you are interpreting as "power increases" is actually the external voltage following the internal voltage of the battery (if the series resistance Ri stays the same). In reality, the internal voltage rises a little bit slower because Ri is dropping slightly with SoC.

That's exactly what all these graphs show. None of these graphs show any power but it can be derived from the state of charge of the iPhone example. Just take all the values, calculate d/dt E and you'll see that power is almost constant.

 

1 hour ago, mr moose said:

Dude I posted several exactly the same, I even pointed how it looks linear in my first post.  Did you read my post where I said that? You tried to claim the resistance changed with SoC now you are trying to claim it doesn't, I'm over this conversation, you are misinterpreting how the system works, misinterpreting how to use Ohms law for said application and most importantly you are ignoring the very NON-Linear charge curve of the cell.     

That's quite condescending. I'm trying to help you understand the logical error you made.If you do it over and over again, I can only point at if from so many different angles.

1 hour ago, mr moose said:

Feel free to say what every you like about it, I'm just glad people designing a lithium BCM aren't going to be reading this and instead will be at stackexchange or eevblog forums.

I do understand them quite well. It's really exhausting to be discussing with people who have a strong opinion but are very close to the ordinate on the Dunning-Kruger-Graph.

 

[Tech Enthusiast]

At this point I am 100% sure the guy is just a really crazy troll that got us all.

There is no way in hell this is serious. I fear for humanity if it is... no one could be this stubborn in his denial of reality. Apart from that one party in that one country, where it seems to be the common thing to do.

[HenrySalayne]

13 minutes ago, Tech Enthusiast said:

us

Who is "us" exactly? A bunch of people with superficial knowledge who fill the gaps with a very strong opinion and stir it up with some insults and being condescending? Then yes, absolutely!

17 minutes ago, Tech Enthusiast said:

There is no way in hell this is serious. I fear for humanity if it is... no one could be this stubborn in his denial of reality. Apart from that one party in that one country, where it seems to be the common thing to do.

q. e. d.

[Obioban]

On 2/23/2022 at 11:41 AM, Doobeedoo said:

It's so weird and lame at the same time. Funny how most selling brands Apple and Samsung have the slowest charging speeds. Come on now. Do better.

So long as you have enough battery life to always make it through the day, fast charging is an anti feature IMO... and any phone that can't consistently make it through a day of use isn't a phone worth owning.

 

I use a 5W charger to charge my phone only-- I only charge overnight while I'm sleeping, so who cares how fast it is? When I wake up, it's at 100%.

 

Slower charging is better for battery health.

 

... I just wish I could limit the max percent it charged to. 100% is also rough on battery, and I rarely go to bed with <50% battery.

[Lurick]

17 minutes ago, Obioban said:

So long as you have enough battery life to always make it through the day, fast charging is an anti feature IMO... and any phone that can't consistently make it through a day of use isn't a phone worth owning.

 

I use a 5W charger to charge my phone only-- I only charge overnight while I'm sleeping, so who cares how fast it is? When I wake up, it's at 100%.

 

Slower charging is better for battery health.

 

... I just wish I could limit the max percent it charged to. 100% is also rough on battery, and I rarely go to bed with <50% battery.

Not sure if it's an Android feature or Samsung feature but my S21 and S22 have a "limit battery to 85%" option on Android 12 (it might have been there on 11 and I didn't see it)

[Doobeedoo]

1 hour ago, Obioban said:

So long as you have enough battery life to always make it through the day, fast charging is an anti feature IMO... and any phone that can't consistently make it through a day of use isn't a phone worth owning.

 

I use a 5W charger to charge my phone only-- I only charge overnight while I'm sleeping, so who cares how fast it is? When I wake up, it's at 100%.

 

Slower charging is better for battery health.

 

... I just wish I could limit the max percent it charged to. 100% is also rough on battery, and I rarely go to bed with <50% battery.

How can it be an anti feature? Really if you use your phone in general a bit more you can never have enough battery. Sometimes mid day you can top it off quick with fast charge and that is awesome. I never charge my phone over night. It doesn't take hours. I only see mostly iPhone users do that.

Slow charging is not better for battery health. Phones improved alot. Really how many times you charge your phone and how has more effect. Some phones can set limits for to what percent to charge to. Maybe some apps.

[Obioban]

38 minutes ago, Doobeedoo said:

How can it be an anti feature? Really if you use your phone in general a bit more you can never have enough battery. Sometimes mid day you can top it off quick with fast charge and that is awesome. I never charge my phone over night. It doesn't take hours. I only see mostly iPhone users do that.

Slow charging is not better for battery health. Phones improved alot. Really how many times you charge your phone and how has more effect. Some phones can set limits for to what percent to charge to. Maybe some apps.

Faster charging is always worse for the battery-- it's just how current battery chemistry works. No amount of phone improvement changes that. I avoid DC faster chargers for my car whenever possible for the same reason.

 

I have zero desire to move away from charging my phone overnight-- that's the only time it's not inconvenient for it to be charging (as clearly I'm not using it while sleeping).

[Doobeedoo]

14 minutes ago, Obioban said:

Faster charging is always worse for the battery-- it's just how current battery chemistry works. No amount of phone improvement changes that. I avoid DC faster chargers for my car whenever possible for the same reason.

 

I have zero desire to move away from charging my phone overnight-- that's the only time it's not inconvenient for it to be charging (as clearly I'm not using it while sleeping).

Early faster phones and also if battery is really getting hot. I've seen many phones with slow charging that over time had worse battery than number of phones with faster charging. Also if you have your phone for years on it won't matter anyway, since battery will degrade over so many cycles of charging in general, be it charges very slow or not.

[RejZoR]

On 2/26/2022 at 7:47 PM, Elijah Kamski said:

Forget the children, think of the environment, then think of how the environment impacts children, in the end of it all, think of the children!

We need to ensure our company, Samsung, is making a positive impact to our children's future, by ensuring that the environment they'll have in the future is preserved. We do this by reducing e-Waste, specifically by removing chargers as everyone has one of those already, right?

Now, in terms of the 25W charger being no different than the 45W charger, and all of you saying that we're just trying to find a way to create money, there is a difference...

In our wallets, have you seen how fat our wallet's are getting?

In terms of benefits to the consumer, you can brag of having a 4 instead of a 2.

Samsung - Think different, but keep following Apple

 

Think of the children! Think of the nature! Also here is fast charge capability for which you need to buy whole new charger, otherwise you won't benefit from it at all. Well, so anyways, here is a charger in its own extra box that we dragged to the store with another truck from another ship that we sent extra from China. Pure idiocy.

[Obioban]

1 hour ago, Doobeedoo said:

 Also if you have your phone for years on it won't matter anyway, since battery will degrade over so many cycles of charging in general, be it charges very slow or not.

I mean, it does matter-- that's exactly the point. Faster charging means battery degradation happens over fewer cycles.

[mr moose]

4 hours ago, Doobeedoo said:

Early faster phones and also if battery is really getting hot. I've seen many phones with slow charging that over time had worse battery than number of phones with faster charging. Also if you have your phone for years on it won't matter anyway, since battery will degrade over so many cycles of charging in general, be it charges very slow or not.

All batteries degrade over time, but fast charging will degrade them faster than slow charging will.  This is a chemical problem with the battery and not a problem you can fix with better chargers. 

 

 

 

 

[Doobeedoo]

50 minutes ago, mr moose said:

All batteries degrade over time, but fast charging will degrade them faster than slow charging will.  This is a chemical problem with the battery and not a problem you can fix with better chargers. 

 

 

 

 

Have you used both type of phones? They are degrade roughly around same. I never said those faster chargers are better in a way to protect the battery, the whole circuitry in the phone is where it's at. Usually battery split in dual cells, temp probes keeping temp cool enough. No matter how slow a phone charges, that battery will still be bad over years of use.