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Question Fast charging, and superfast charging

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M3dad01

New member
Dec 31, 2015
3
0
does the 45W Support S21 Ultra ? I'm Currently using Belkin 20W charging brick with usb c cable that came with the device and it gives me fast charging
 

RomBox

Senior Member
Nov 30, 2011
201
29
singapore
does the 45W Support S21 Ultra ? I'm Currently using Belkin 20W charging brick with usb c cable that came with the device and it gives me fast charging
the 45w charger for sure can charge s21u, but will be limited to 25W speed at most. and even if the phone show "super faster charging", it may not at 25W even at the 0-50% range: when the phone temperature over 36 degree, it will switch to 9W speed. my location the climate is very hot, thus I have to put the phone above a small fan to make it can charging at 25W speed longer.
you can install "3C battery manager" to check the charging speed. for s21u around 100%/h means 25W charging.
 
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blackhawk

Senior Member
Jun 23, 2020
4,078
1,059
Faster charger that came with my Huewei mate 20 pro doesn't work ...

Sigh

Remember fast charging will not engage if the battery is cold, roughly 60-50°F or below.
Best charging starting temp is 85-90°F. It will disengage somewhere above 100°F.
Cold charging Li's can cause Li plating and should be avoided.
 

amirage

Senior Member
Sep 1, 2010
1,532
316
Dubai
OnePlus Nord N100
Hi Comrades, I have a question about charging the phone using my iPad 12W charger. The article states a lot of technical terms regarding power delivery which I'm not sure if the iPad has. Has anyone tried charging the phone using an iPad 12W charger? I do have the 25W Samsung charger but I'm not very keen on fast charging my phone on a daily basis due to the ill-effects of fast charging. Look forward to your comments.
 

RomBox

Senior Member
Nov 30, 2011
201
29
singapore
Hi Comrades, I have a question about charging the phone using my iPad 12W charger. The article states a lot of technical terms regarding power delivery which I'm not sure if the iPad has. Has anyone tried charging the phone using an iPad 12W charger? I do have the 25W Samsung charger but I'm not very keen on fast charging my phone on a daily basis due to the ill-effects of fast charging. Look forward to your comments.
you can turn off fast charging and superfast charging in the phone's settings.
 

OnMy2ndGP

Senior Member
Oct 21, 2010
381
151
MD
Samsung Galaxy S21 Ultra
I have the Samsung 25w charger, and when using it it appears the phone will only either cable charge or superfast charge. It wont also fast charge. I want to maximize the battery life span of the phone, and cable charging is inconveniently slow, and I figured that fast charging would be a happy medium between that and maxing it out. I was under the impression that it's the phone that dictates the rate of charge it will accept from the brick, and the brick only determines the maximum deliverable current. If I understand correctly, we can use samsung's 45w charger, but the phone will obviously only allow 25w from it. I'm puzzled why when using the 25w charger the phone can't just accept 15w when set to only fast charge. Is this a bug?

OMG! Many replies but maybe 1 person with the same issue.

I noticed the exact behavior as you. I have a S21 Ultra, I purchased official Samsung 25W charger from T-Mobile store. I did ask the check boxes, in checking save what different combo possible. She result as your device. It never says fast charging. The only time I see it display as fast charging us wirelessly on an older Samsung fast charging pad. It only day cable charging or super fast charging. Like you I was expect 3 levels of charging: cable charging (slowest), fast charging (mid level) & super fast charging (full 25W fastest for our device). Again I can only manage to get fast charging via wireless pad. Only cable charging and super fast charging with the 25W brick. It's strange to me too.

I also noticed that my device doesn't have a "5000" mAh battery. It's actually a 4855 mAh battery. For marketing purposes they much be rounding up. I still feel cheated. 🥺🤣
 
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peterg21

Senior Member
Dec 9, 2011
112
68
OMG! Many replies but maybe 1 person with the same issue.

I noticed the exact behavior as you. I have a S21 Ultra, I purchased official Samsung 25W charger from T-Mobile store. I did ask the check boxes, in checking save what different combo possible. She result as your device. It never says fast charging. The only time I see it display as fast charging us wirelessly on an older Samsung fast charging pad. It only day cable charging or super fast charging. Like you I was expect 3 levels of charging: cable charging (slowest), fast charging (mid level) & super fast charging (full 25W fastest for our device). Again I can only manage to get fast charging via wireless pad. Only cable charging and super fast charging with the 25W brick. It's strange to me too.

I also noticed that my device doesn't have a "5000" mAh battery. It's actually a 4855 mAh battery. For marketing purposes they much be rounding up. I still feel cheated. 🥺🤣

Just a small note regarding wireless. I purchased the 9W Samsung Charger for my Note9 and my S21 Ultra primarily to spare the port (My Note 9 is apparently having port problems). Anyhow, like you, I am looking to make this battery last as long as possible and wireless fast charging is not really what I want. There was, even with the 9W wireless charger, somewhat more heat than I was comfortable with. So I turned off fast wireless charging and looked to see how much slower it would be. Interesting. Just charging between say 50%-70% I noticed the speed of charging seemingly was not slower (I was not being scientific about it) but the temperature dropped whilst charging from 36C to 30C. Quite happy with that.
 
Feb 2, 2021
8
5
I can confirm, 25w brick does not charge in fast regular mode (15w) on my S21, with a usb-c/usb-c cable you can just use super fast charging and regular charging.

You have to take an old samsung brick "adaptive fast charging" with a regular usb-a cable /usb-c to be able to use the fast charging mode.

Btw fast charging only saves 10min (on S21) compared to regular normal charging so there is not too much interest in using it on new devices
 
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Quazza

Senior Member
Oct 22, 2013
71
14
Ok excuse my ignorance here , but what exactly do I need for super fast charging ? My 40w Huewei doesn't do it , my Samsung charger with "adaptive fast charging " doesn't do it ....pretty confused at this point !
 
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blackhawk

Senior Member
Jun 23, 2020
4,078
1,059
Ok excuse my ignorance here , but what exactly do I need for super fast charging ? My 40w Huewei doesn't do it , my Samsung charger with "adaptive fast charging " doesn't do it ....pretty confused at this point !

You need a minimum 25w or higher brick and cable that's compatible with the Samsung fast charging protocols.
If that's not the problem than either the settings/software or firmware or phone hardware is at fault.
It's quit aggravating to troubleshoot.

So the first step is to start with a know good Samsung fast charging 25w brick and cable.
Google it but one thing you can try is to discharge the phone until it auto shuts down then charge to 100%, allow a few minutes at 100% before disconnecting it. Repeat 2X. That should recalibrate it. If that was the cause it should fix it.
That fixed my 10+ which was fast charging erratically.

Remember to start the charge with a battery temp of 80-85°F*. It an electrochemical reaction and Li's don't like charging in the cold. Fast charging will disable if the battery temperature gets too low.
Don't exceed 100°F or so; at 102°F or so it will stop charging.
I aim for a temperature of 85-95°F at the end of the charge cycle.

*at an ambient temperature of 70°F this should keep it within it ideal charging temperature range.
Cover it if it's cooling down while charging; don't let it drop below 80°F!
 
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OnMy2ndGP

Senior Member
Oct 21, 2010
381
151
MD
Samsung Galaxy S21 Ultra
XDA just covered this in their article:

Unless a charger has USB-PD PPS they will only FAST Charge @ 18w with fast charge on (super fast on/off wont matter as it will be off). If you are getting super fast charging then you are getting the expected 25w which is totally fine and not bad for battery. You will get super fast with the samsung 25w adapter and maybe the previous series 45w adapter.
☝🏾☝🏾☝🏾 Thanks for pointing out that article. It clears up a lot of confusion.

Ok excuse my ignorance here , but what exactly do I need for super fast charging ? My 40w Huewei doesn't do it , my Samsung charger with "adaptive fast charging " doesn't do it ....pretty confused at this point !
Read the article mentioned above. Hope that helps.
 
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  • 3
    Probably a firmware/software glitch.

    Fast charging will not enable if battery temp is too low.
    To avoid Li plating the battery temp should be a minimum of 72°F or higher, the preferred minimum is 80°F.

    Using the 45 watt brick may shorten battery life.
    Fast charging with the 25 watt brick appears to do little damage.
    Li's prefer brief, frequent midrange charges ie 40-65%. Avoid discharging below 30% and charging beyond 90% although 80% is a better top limit.
    3
    Ive seen this same type of issue as well with 2 different chargers. One charger (45w pd) will fast charge with super turned on but not fast, notification only says fast charge. The second (39w qc3) will fast charge with regular fast charging turned on, but turning on super does nothing. Charge times are the same with both chargers on regular charging and fast, with 0 differemce between fast charging and super.

    XDA just covered this in their article:

    Unless a charger has USB-PD PPS they will only FAST Charge @ 18w with fast charge on (super fast on/off wont matter as it will be off). If you are getting super fast charging then you are getting the expected 25w which is totally fine and not bad for battery. You will get super fast with the samsung 25w adapter and maybe the previous series 45w adapter.
    1
    if you want fast charge ..... deactivate superfast charge should be the solution ! Isn't it ?
    No, if you only activate fast charge (with superfast deactivated) and use the 25w brick, the notification in the shade says cable charging, and that takes like 2hrs to charge the phone.
    1
    I'm curious if anyone here has a 25w brick that could confirm if this behavior is present globally, or if this is something just on my device? Only activate fast charging in the battery settings, plug the phone in with the 25w charger, and look in the notification shade and see what the charge rate is tagged as. I'd be grateful if someone would confirm this.
    1
    XDA just covered this in their article:

    Unless a charger has USB-PD PPS they will only FAST Charge @ 18w with fast charge on (super fast on/off wont matter as it will be off). If you are getting super fast charging then you are getting the expected 25w which is totally fine and not bad for battery. You will get super fast with the samsung 25w adapter and maybe the previous series 45w adapter.
    ☝🏾☝🏾☝🏾 Thanks for pointing out that article. It clears up a lot of confusion.

    Ok excuse my ignorance here , but what exactly do I need for super fast charging ? My 40w Huewei doesn't do it , my Samsung charger with "adaptive fast charging " doesn't do it ....pretty confused at this point !
    Read the article mentioned above. Hope that helps.