Phone battery night terrors  - Page 1
Forum section: electronics / general

author: PerranOak
author_rank: Frequent Contributor
timestamp: February 22, 2022, 08:11:42 am
content: Coming from a time when the best thing to do with a battery was to drain it fully and then charge it up to 100%, I am now confused.I am told, on the Internet, that now it is best (for phones) to drain them to about 40% and then up to about 80%. I guess this is right?My next question is should I turn the phone off at night? Will this help to keep battery health high?Cheers.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 22, 2022, 09:46:13 am
content: Your original information was wrong. I suspect you are referring to NiCd batteries. Even before NiCd's, we had and still have lead acid batteries. Draining either of those battery types completely before charging was bad. NiCd's were noted to have "memory." That is, if you repeatedly discharged 10% of the available charge, then available charge got lessMore recent lithium based batteries are more finicky. EDIT: But don't have memory. As I recall, that memory effect was first noticed in satellites. It really was not something that plagued the casual user.

author: golden_labels
author_rank: Super Contributor
timestamp: February 22, 2022, 10:42:48 am
content: Lithium-ion batteries should not be discharged below 3V. Which is not a concern of you as the user, as the control circuitry will report it as 0% much earlier, and will cut if off completely if it ever goes near that value. The only concern is, theoretically, keeping the battery at its maximum volatege (4.2V) constantly. So there is a grain of truth in “don’t charge above 80%”. But you would need to carefully plan charging through the entire lifespan of your phone to prevent that, while risking it will run out of juice when you need the phone most. So hardly worth the effort.(1)Turning the phone off while unused will of course reduce energy use and wear in general: nothing to do with li-ion cells in particular.NiCd batteries didn’t have memory effect either in normal use. The effect was only present in very rare scenarios not found in consumer gear and wasn’t an actual drop in capacity, but a perceived one due to not charging the battery fully.(1)Said by a person, who does that out of habit. Unless I need something to contain maximum charge, I disconnect devices as soon as I see they are fully. But that’s more satisfying my brain than actually changing something.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 22, 2022, 07:34:07 pm
content: Note that these days, software on many mobile devices already takes care of that - usually through some options. So you can set the charge to stop below 100%. And, you get a low batt warning when it goes below 20%.But does keeping the SoC (assuming the SoC is correctly estimated, to begin with) between 20% and 80% really increase battery life?While going too low or staying at the max voltage for too long will reduce battery life, if you're doing neither of those extremes, is the above going to change anything? Not really sure.And, if you're always between 20% and 80% SoC, aren't you using only 60% of the rated capacity (which - I know it's obvious - but is not that far from just half of its capacity!)? So, you get the inconvenience of having to charge almost twice as often for a given use pattern. Up to you to define if that's worth the trouble.

author: Halcyon
author_rank: Unknown
timestamp: February 22, 2022, 11:03:51 pm
content: Use the phone as you need and just plug it in and forget about it until you need to take it off the charger. The phone will take care of the rest.This has been the case since even back when the Nokia 5110 was around.Quote from: PerranOak on February 22, 2022, 08:11:42 amIt makes no difference.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 22, 2022, 11:13:44 pm
content: Turning the phone off at night makes a small difference. How much depends on the phone and a bit the local reception.

author: Halcyon
author_rank: Unknown
timestamp: February 22, 2022, 11:38:42 pm
content: Quote from: Kleinstein on February 22, 2022, 11:13:44 pmCan you explain what you mean? If you have your phone plugged in, the battery isn't discharging. The phone is powered entirely by the AC adapter.

author: IanB
author_rank: Super Contributor
timestamp: February 22, 2022, 11:59:12 pm
content: Quote from: PerranOak on February 22, 2022, 08:11:42 amAs others have said, just let the phone take care of itself. Use it normally and charge it when it needs charging. I would note that my phone automatically backs itself up when it is left plugged in overnight, so I do that regularly.But what do you mean by "turn it off"? Do you mean powering it down and switching it off, so that when you switch it on again it has to go through its boot screen and start up sequence? That would be strange to me. I've never thought about doing that with a phone. The only time I see the startup screen on my phone is after a software update when it does a restart.

author: PerranOak
author_rank: Frequent Contributor
timestamp: February 23, 2022, 07:43:20 pm
content: Thanks all. I did turn it right off (boot screen).The basic point is that I’m trying to delay the time until battery replacement.

author: IanB
author_rank: Super Contributor
timestamp: February 23, 2022, 08:27:28 pm
content: Quote from: PerranOak on February 23, 2022, 07:43:20 pmFirst of all, I have not had the need to replace a phone battery in 25+ years of using mobile phones. So it's not something I stress about.But secondly, if you really are paranoid about this, then the best thing to do is to charge your phone up to 80% and no more, then use it down to 20%, then charge it back up to 80%. This, of course, is going to be a lot of trouble.If it really mattered very much, then the phone itself would have an 80%/20% mode to do this automatically. But most phones don't have such a mode (do any?). The absence of such a mode suggests you are worrying too much about it.

author: Halcyon
author_rank: Unknown
timestamp: February 24, 2022, 02:06:55 am
content: Quote from: PerranOak on February 23, 2022, 07:43:20 pmCharge it when it needs charging (or when you think you might need to use it).Leaving it plugged in for long periods will have no impact on battery longevity.Turn it off only if you want it turned off. It has no impact on battery longevity.Don't leave or store your phone in hot places (like in a car on a sunny day)If storing your phone for extended periods, don't store the battery discharged.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 24, 2022, 02:51:03 am
content: While I agree with most of your points, I'm less convinced by this one:Quote from: Halcyon on February 24, 2022, 02:06:55 amIf you do that, unless there is some software provision to limit the SoC to a certain level way below 100% (80% is considered a safe bet) - which actually many laptops have, but for mobile devices, it's less common - then you're basically keeping your battery at 100% SoC for long periods of time, even if the charge itself stops, of course, when it reaches that. Just "storing" a battery at 100% SoC for long periods of time is known to reduce lifetime - which is why they are commonly charged at around 80% for storage, and sold at this level.Now of course it's all in defining what "long periods" mean. If it's a few hours, it's probably not a big deal whatsoever. If it's weeks, OTOH...

author: Halcyon
author_rank: Unknown
timestamp: February 24, 2022, 04:52:18 am
content: Quote from: SiliconWizard on February 24, 2022, 02:51:03 amBattery management is extremely well developed. What a consumer device reports as "100%" might actually be less than the native cell capacity. It all depends on the chemistry, device, how it's been designed, etc... Mobile phones are specifically designed to be plugged in by the consumer in the evening and stay that way until the following day. Even abnormal use has been well tested and is tolerated by these types of products.One good real-life example is my department's on-call phone. For 95% of the time, it stays switched on, plugged into mains power (we just divert it to our work phones). The phone itself is about 5 years old (Samsung Galaxy A5), yet the battery still holds a good 2.5 days of charge.Unless you have some extreme edge-case, there is no point in over-thinking things. Just use the product as it was designed.

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: February 24, 2022, 05:27:02 am
content: Halcyon's advice is very solid here. There's simply too much inertia from previous battery technology restraints that bleeds into areas long since left in the dust.Just watch the ambient heat. Try and keep the phone cool. Any variance to that policy you can expect the battery life to take a hit.Yes, there is a concern with lithium reaching very low capacities (<5%), but all you need to do is plug it in before it gets to that stage and keep it cool. Or consider turning it off!

author: Psi
author_rank: Super Contributor
timestamp: February 24, 2022, 09:29:28 am
content: Quote from: IanB on February 23, 2022, 08:27:28 pmSome phones do, but it's pretty rare.I guess they would rather sell you a new phone than make your current one last longer.At one point I heard a new version of android was going to have that feature, but I didn't hear any more after that.You could totally build a DIY system to do it. Use an ESP8266 mains relay module and a quick and dirty android app to turn the relay on or off depending on current battery level.

author: Karel
author_rank: Super Contributor
timestamp: February 24, 2022, 12:10:13 pm
content: Imho what's much more important, is to charge with a low current.Do not use the supplied charger that comes with your phone.Do not use any kind of fast charger.Instead, use a simple (USB-A) wallcharger that can only supply a fixed 5 Volt.In my case, I connect my phone to my desktop pc (USB-A port!) for charging. With Android you'll usually seea message that it's charging slowly. If that is the case, you'r fine.I noticed that most desktop pc's supply the 5 Volt on their USB ports also when switched off.So, I can charge my phone overnight by using my desktop pc as well.Do not use a USB-C of your pc port because they can supply more power.This way my old google Nexus 6p (Huawei) lasted 5 years without replacing the battery.

author: Halcyon
author_rank: Unknown
timestamp: February 25, 2022, 01:31:28 am
content: Quote from: Karel on February 24, 2022, 12:10:13 pmPerhaps someone who knows more about battery chemistry can weigh in on this one, but my understanding was that lithium batteries would accept quite fast charging compared to other chemistries, provided that the heat can be kept down.With smartphone smart chargers, they slow down charging as the battery approaches full.Although if you are charging overnight and charging time isn't important, it's not going to harm the battery if you charge it slowly.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 25, 2022, 03:04:33 am
content: Quote from: Psi on February 24, 2022, 09:29:28 amThere's an app that will do it if the hardware is capable of it.https://f-droid.org/en/packages/mattecarra.accapp/

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 25, 2022, 03:48:17 am
content: Quote from: PerranOak on February 23, 2022, 07:43:20 pmfalse economy... frequently touching (esp pressing it hard for few seconds) the side on/off button will wear it out quickly. when that button is screwed, your smartphone is screwed, however pristine your battery is.. my samsung phone never turned off, unless some apps make it hanged. its been on charger at night or home and removed only when i go out or pick up/make call/text, its charge and forget thing for 5-7 years now. i tend to replace to new smartphone earlier than to replace the battery. even if i do, its quite hard to find battery replacement that performs as it was when i bought the phone new, i guess they are all bunch of unsold battery spares manufactured 5-7 years back when i bought the phone, and diminishing performance while in stores. ymmv.

author: Halcyon
author_rank: Unknown
timestamp: February 25, 2022, 06:07:50 am
content: As a side note, I remember the uproar when phone manufacturers started making batteries non-removable. I think it largely started with the Apple iPhone and most other manufacturers have since followed suit. I was guilty of dismissing the idea as "stupid" and even went as far as entertaining the idea that it was somehow driven by planned obsolescence.Thinking back over all the phone's I've owned, I can't think of a single time I actually bought a replacement battery for a phone because it had "warn out" and typically I would charge them every single night (even my Nokia's that lasted several days). Even to this day I still have most of my old phones, going right back to my Nokia 5110. The battery still lasts a few days (last time I tested it in 2017 before the 2G network was shutdown in Australia).