Charge Galaxy S8 battery

View Comments

• Thanks for the information here.

  I have an issue with my S8 fast wireless charging:-

  1. In Settings — Device maintenance —Battery —menu key (3 vertical dots near top right)– Advanced settings, I turned on both fast cable charging and fast wireless charging.

  2. When I put S8 device on the wireless charger pad, the "fast wireless charging" option is automatically grey out and I cannot turn it on back

  3. As a result, the charging is normal around 3 hours.

  Please assist.

  • You cannot change fast charging setting when the phone is connected to a charger or stay on a wireless charging pad. This is normal. It’s designed on this way. You can change such settings before connecting the charger.

    During charging, you can wake up the screen. In the lock screen, it should indicate the charging status. It also tell you whether it’s fast charging.

    If it says only charging, not fast charging. It means fast charging is not activated. For fast wireless charging, you should connect a Samsung’s adaptive charger (like the one in your S8 box) to the charging pad. Other branded charges will not work with fast wireless charging.

    Also, if you are using a thick case, you may also remove it to test.

• I use this wireless charger type https://www.amazon.com/Samsung-Wireless-Charging-Charger-Warranty/dp/B01BMDQ9U8/ref=as_li_ss_tl?ie=UTF8&qid=1492328625&sr=8-3&keywords=samsung+fast+wireless+charger&linkCode=sl1&tag=ggos8-20&linkId=e9e4810cf76ac9218eacfa8ffbf5abaa

• Hi Simon,

  Thank you for your swift response.

  When I wake up the screen, in the lock screen it’s fast charging actually which mean fast charging is activated. I have also removed thick case but still I get normal charging.

  The only thing I have not try is to connect a Samsung’s adaptive charger (like the one in S8 box) to the charging pad. What I have done was, I just used usb 2.0 cable (provided in S8 box) to connect to the charging pad. I do not know that the adapter provided in the box is for fast wireless charging :). Thanks for reminding this and I will try that.

  • If fast charging is shown in the lock screen, then it means the adapter is correct type.

    You may check: whether the USB cable is inserted tightly on both ends.

    Slow charging can also be caused by background activities. If you really want to test, you can power off the phone then check the charging time. But this is too obtrusive because you will miss all calls when phone is powered off.

    You can also compare charging time with fast wireless charging off.

• Hi Simon,

  So that's mean I do not need to use adapter?

  I confirmed USB cable is inserted tightly on both ends. I have also tried to charge offline using wireless charger. Time taken is same with online charge approximately 3 hours.

  • Then you can try the adapter in your S8 box. The adapter you used is correct in type because the phone shows it's fast charging. But the actual output power of the adapter may be lower than specifications (although it's rare, but possible).

    Btw, is your phone S8 or S8+?

• My phone is S8. I tried to use the adaptive fast charging in the S8 box and wireless fast charging took more time than cable fast charging. In lock screen, it is showing fast charging for both wireless fast charging and cable fast charging. Cable fast charging took me around 1.5 hours while wireless fast charging took around 3 hours. This is from 0% - 100%. I am not sure if this is normal for wireless fast charging but if it is so, I would rather use cable fast charging instead. I was just wondering if both charging type are fast charging, the time taken should more or less the same.

  • It's normal. Fast wireless charging is always slower than fast cable charging as explained in this guide. Fast wireless charging can only charge up to 5v 1.5A (7.5w). It's faster than normal wireless charging which can charge the battery up to 5v 1A(5w). Fast cable charging can charge up to 15w (9v 1.67A) for the first 50%-60%. For the rest 40-50%, up to 10w(5v 2A).

    Anyway, 1.5 and 3 hours charging time are still in normal range, although they are on the higher end.

• I read this guide but I did not fully understand when it mentions about voltage and Walt. At least I know the thing. Nice guide anyway..

• I noticed that you said that once the battery is fully charged, there will be a green LED light on the phone to indicate that it is fully charged. Well, it is true on my previous note3, note4 & note5. but I realized that my new s8+ does not have the green LED light even when it is at a 100%. It will continue to show red LED light. Is there a problem with my phone or is someone else also have this problem with their new s8 or s8+ ??? please let me know.. thanks

  • It will turn green when it's fully charged. 100% doesn't mean it's fully charged.

    You can try to turn off and on Settings - display - LED indicator.

    You can also try to reboot the phone to see whether it helps.

• and thank you for your guide.

• hi, i have a some questions. I hope i get help from you. thanks
  1. if I charge my phone overnight until it is fully charged, but did not disconnect it from the charger, will this harm and shorten the life of my s8+ battery??

  2. for Iphone batteries, it was suggested not to fully charged the battery, because once the battery reaches 100% but still charging, it will create a high stress on the battery and shorten the life of the battery. I am not sure if this is the case with the s8+ batteries??

  3. You mentioned not to disconnect the phone from the charger if it is not fully charged. If by doing so, will it do harm and shorten the battery life ??

  • 1. As mentioned in the page, if it's wireless charger, there is no trickling current and no impact on the battery. For charging through USB, one battery is fully charged, a small tricking current will be maintained as the phone cannot shut off the wall charger. This may slightly affect battery. But you should not worry about it. The impact is very marginal. You should enjoy the phone and you need to replace the battery anyway if you want to use it for more than 3-5 years.

    2. Does Apple suggest this? It's totally wrong.

    3. Just don't do it often. Some owners have the habit to "top up" the battery. It's not necessary. Charge the battery only when you need to do so. Try to charge it to full when charging.

• My query is when iv bought and set it up in the shop then i got back to home how many hours should it be on charging in particular

  • Once the battery is fully charged (the LED should turn to green, and it should state "charged" in lock screen), it is safe to disconnect the charger.

    It is NOT necessary to connect to the charger after battery is fully charged, even for the first charge.

    Enjoy your new toy.

• Hi is there a certain battery percentage that I should my 8 plus? I don't want to make the mistake of over charging.

  • Galaxy S8 battery will not be overcharged. The battery has its own protection mechanisms for this.

• simon are you sure that s8 or s8+ do not have such overcharging problems? just want to double confirm. and if it has so, can u tell me the best way to prolong the age of the battery

  • All today's smartphone battery has been overcharging protection mechanisms. Not sure why you are still concerning overcharging issue. It's a solved problem for Li ion battery. Anyway, this is a community site. Nobody can guarantee anything.

    For expensive phones like S8 or S8+, you should consider how to get more value (entertainment, productivity..) from the phone. Instead of worrying about the life span of the battery. Normal Li ion battery has a shelf life of about 3-6 years. Even you don't use the phone, after a few years, the battery will lose capacity significantly. If you are a heavy user, you may need to replace the battery after less than 2 years. The key point is to enjoy the phone as much as you can. For charging, you charge the battery only when you need to do it. Don't fully drain the battery often. Disconnect the charger if it's convenient to do so after battery is fully charged. Don't use the phone heavily when it's being charged.

• Hi. What percentage does my battery have to be before I can charge it
  ..thanks

  • At any percentage.

    But you should charge the battery only when you need to do so.

• Is it bad to disconnect charger if the phone is not fully charged? I was charging my S8 the other day but was using my computer to charge it via USB and it took so long that my shift was done already and so I had to disconnect at 87%...

  • Just do not do it very often. It is OK if you do it a few times.

• On my last phone, I used an Anker PowerDrive 1 cigarette adapter that uses Qualcomm QuickCharge 3.0 technology. Is QC 3.0 compatibile and safe to use with the Galaxy S8+? Obviously I would continue to use the charging cable that came with the S8+. I haven't been able to find information online that answers this question. Any help would be appreciated.

  • Galaxy S8 only supports quickcharge 2.0, not 3.0 due to Exynos chips used in international market.

    As QC3.0 is backward compatible to QC 2.0. it aloud be no issues to use yours charger for Galaxy S8.

    I don't think there are any safety issues of the charger is still in good state.

• I would like to know at what battery level is it ideal to charge the phone ,like is it below 30% 20% etc so that the phone battery lasts for more than 2-3 years. And is there any problem for charging phone more than one time a day?

  • You need to charge the phone only when you need to do it and when it's convenient. Don't just read the percentage. But when you charge the battery, you should wait till it's fully charged. Minimize the usage when charging.

    Charging often will affect battery life. But if you have to charge the phone, you should do. Otherwise, why did you buy the phone?

    You get the most from the phone if the phone can improve your productivity, or/and if the phone makes you happy/entertained.

    Anyway, you should enjoy the phone.

• I have a question, I have a fast wireless charging adpater, and I always use it as a stand, so this is the scenariosa: my phone is fully charged and I take it and play for 10 min and put it back to charging until next 100% and take it. so is this harmful or it's noting? Thanks!

  • It is not a good habit. You should charge the phone only when you need to do it. It is not necessary to top up frequently.

• Hi I recently bought my S8+ and I had been using it heavily everyday to play games. Im charging it almost 3 times a day. Will this heavily affect my batterly life span. And should I remove the cover to charge to prevent the battery from heating up?

  • it is not necessary to remove the cover. But you should NOT play games when charging.

    You may have to change battery after 12-18 months based on your usage. If you enjoy the phone, spending the $50 (to $100 depending on your region) for a new battery after one year is worthy.

• Hi I got my new Samsung8 only last week and I'm wondering if I might hav a faulty battery.i do use my phone to do everything e.g. mobile banking fb gmail hotmail etc and I'm finding that I need to charge the battery at least twice daily if not 3 times some days.is this normal?thank u Elaine

  • What's the screen-on time? You can check battery usage in Settings -Device maintenance- battery.

• "You will replace the Galaxy S8 or S8+ battery within 12-24 months for heavy users (e.g., charging the battery more than once each day in average), 24-36 months for normal users."

  Bit hard when you can't change the battery ?

  • You can still use the battery. But the capacity of the battery may be 20-30% lower than original.

    • Hi Simon, I get that the battery capacity will diminish, but my comment was related to the article which advises you will need to change the battery after 24-36 months. How do you change a fixed battery ??

      • You should try to visit Samsung service centre to replace the battery. Some handphone shops can also do it.

• So does that mean I actually need to charge it at 1%, if I spend all day at home, I just leave it till its nearly dead OR ... or what would a good base level be..... 10%,15%,30%. ????

  • It's a bad idea to purposely let the battery drain to 1% often, then charge it.

    Charge the battery when you need to do so. At 15%, the phone should remind you.

• What percentage should the s8 be before I charge it? Cause I wait till it's about 20% on maximum power saving mode to charge it. Took a day and some hoursnto charge it. Is that fine?

  • Charge the battery when it is needed. Try not to use the phone heavily when charging.

    When the battery level is less than 15%, S8 would remind you automatically.

    Try not to drain the battery completely (or less than 5%) frequently.

    It is not necessary to "top up" battery if the battery can last till you can charge it later.

    "Took a day and some hours to charge it." It seems something wrong. It should take less than 2-3 hours with a normal wall charger.

• what happens if s8 or s8+ is overcharged many times?

  • Galaxy S8 or S8+ cannot be overcharged. Once the battery is full, the circuits in the battery and in the phone will prevent any overcharging.

    But if you charge the battery when it is not necessary, it may increase the unnecessary wear and tear.

    Anyway, it's not necessary to worry about overcharging.

• Is it okay to charge it around the 50% mark each day? I try to wait until it gets down to 15% but it ends up being at a time when I'm working the day after. Thanks.

  • It's not necessary to wait till 15%. At the same time, there is nothing wrong if you often charge the phone when the battery level is lower than 15%. 15% actually is an arbitrary number. Samsung uses this one too remind you the low battery juice left.

    You should charge the Galaxy S8 battery when it's needed. For example, if you think the 50% battery can last till you have time to charge it. Then it's not necessary to charge it.

    If the battery drains faster after it decreases to 50%, very likely, you should re-calibrate the battery by using it till less than 5% a few times.

    Anyway, don't fully drain the battery (i.e., don't let the phone powered off by itself due to low battery).

• Hello and thanks for the guide!
  I have a question. Some forums (eg. XDA) talk about the battery capacity that you can find with a file explorer in sys / class / power_supply / battery / fg_cycle and fg_fullcapnow. The two files show you the load cycle and the battery capacity. Now I have 100 cycles with 3080mAh on my S8+. Are these system measurements real? Thank you!

  • Yes, it's the most accurate estimation. But it's not a measurement. Don't read too much about such readings. Screen-on time depends on many other factors as well.

    It is better to try to get the most from your phone: enjoyment and productivity. You should get a new battery after 2 years if you want to use it for another 2 years or a new phone.

    I recommend people to read these numbers only when they want to buy a secondhand phone.

• Hello! Did I notice anything lately over that file fg_fullcapnow? I've loaded the phone only wirelles normally from 30% to 100%. It starts to increase that approximation value and has reached 3130 mAh from 3080mAh. So if you load it normally, that value tends to 3300mAh. Does it have regenerative power? Thank you!

  • They value is an estimation. It always fluctuates. But over time, it should decrease no matter how you charge it. If you charge it properly, the speed of the decrease may not be so fast.

• Hey, so I was wondering if while my s8 is plugged in, and I am using it, does it use energy straight from the battery of the phone or the outlet? Thanks!

  • From the battery. It's different from laptops. Your battery is actually discharging - charging.

• Hello! I dropped the S8 + in favor of Note9. I see that many topicals recommend a 40-80% charge for a better battery life. Is it recommended or good for old batteries? And a second question. The new generation Samsung batteries have the rated capacity (ex Notes9-4000mAh) or less as a result of technological process or software limitations. I'm showing 3750 in the Aida64 application. Thanks!

  • Productivity and convenience should be the top priority for you. Most people will change phones after 1-3 years. Don't worry about battery lifespan unless you are a heavy user and have to charge the phone more than once a day. If you are a heavy user, you just need to replace the battery every 1 to 1.5 years. Charging the battery too often will also have a negative impact on the battery. Charge the battery only when you need to do so (the battery cannot last till you can access a charger).

    Aida64 should report the battery capacity based on the specs of the battery, not the actual capacity. So for Note 9, after two years, it should still report 4000mAh. The value reported by the charge counter at the time when the battery is fully charged may be close to the actual capacity. But the estimation is not accurate. For new phones, it can be higher than the capacity. For older phones, it is usually lower than the capacity. It is just an indication. If the reported value is consistently and far lower than the capacity, and you feel the screen on time becomes shorter, you may check or replace the battery.

    Please note, estimation from these apps are not so accurate.

• Thanks a lot for answers!
  I've read many topicals on the XDA related to the real battery capacity and load modes. I used AccuBattery several times, but it shows me a full load at 3680mAh and I uninstalled it. In fact, Aida64 reads charge counter because other files like fg_fullcapnow are no longer accessible without root. Autonomy is excellent on Note9 but curiously I was interested in an application real battery monitoring. Many say that Samsung batteries do not have that chip like Aplle batteries to read the exact capacity. Also,i wanted to ask if wireless charging is less intrusive than wire charging, there are no voltages at the charging terminal.
  Thank you and respect!

  • The actual capacity can be estimated with embedded chips. It's still an estimation, not a measurement.

    As a user, you may just monitor screen on time. The capacity doesn't always translates to screen on time linearly.

• I have a Galaxy s7edge that I don't use very much. Since I don't charge it often it doesn't seem to hold a charge as long. Is there any way to build the battery life back up?

  • Unfortunately, there are no easy solutions. Li-ion battery will degrade with time even you do not use it. The shelf lifespan is only about 5 years. For the storage, manufacturers usually charge it to 50%. If you do not use the phone for a long time (a few months), you can try to charge it to about 60%, then power it off.

    For a seldom-used working phone, it is better to always keep it on and turn on power saving. But you should charge it before it is fully discharged. If you charge the battery, do not stop charging until it is fully discharged.

    Anyway, if the phone is more than 2 years old, the battery may lose about 20-50% capacity even you seldom used it.

• Thank you for the information.

• Hello! I would like to ask you about the temperature that I understand is harmful to li-ion batteries. I have a Samsung Note 9 exynos and tested the four types of charge with the 3C Battery Monitor program. At fast wireless charge the temperature reaches up to 37.7 ° C. Normal wireless charge reaches 35.9 ° C. Fast cable charging 34.8 ° C and normal cable charging 30.8 ° C. Do these fast charge temperatures affect the battery life? To what temperature is the battery safe and which is the life of a Note9 battery? Thanks a lot!

  • Normally, the upper limit of the charging temperature for most Li ion batteries is about 45 degrees Celsius. (The operating temperature limit should be far higher).

    You should not worry about the charging temperature because all smart phones and the battery will regulate the charging current automatically to make sure the temperature is in the designed range.