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Cell phone charging
- Thread starter rainforest
- Start date
Derek Kessler
Active Member
Nope. Phones use a different formulation and are designed to be charged to 100% on a daily basis.
If by "formulation" you mean chemistry, then I partially agree - phone and car batteries have different chemistry but general battery principles still apply - after all, they are still Li-Ion batteries. Battery in a phone always charged to 100% will degrade more than in a phone changed to 80-90%
I found this in the following link:
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
"Li-ion does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge because a high voltage stresses the battery. Choosing a lower voltage threshold or eliminating the saturation charge altogether, prolongs battery life but this reduces the runtime. Chargers for consumer products go for maximum capacity and cannot be adjusted; extended service life is perceived less important."
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
"Li-ion does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge because a high voltage stresses the battery. Choosing a lower voltage threshold or eliminating the saturation charge altogether, prolongs battery life but this reduces the runtime. Chargers for consumer products go for maximum capacity and cannot be adjusted; extended service life is perceived less important."
I have decided that phones can only last 2 years and one thing or another will go wrong. Even if the phone physically lasts, the OS will advance and your phone will not be supported. Soon thereafter the apps will start to migrate to the new operating system and will no longer work on your phone.
So just don't worry about it and get a new phone every 2 years. [insert "You paid umpteen zillion dollars for a car, you can afford a new phone" statement here]
So just don't worry about it and get a new phone every 2 years. [insert "You paid umpteen zillion dollars for a car, you can afford a new phone" statement here]
pilotSteve
Active Member
Also: what does "100%" really mean anyhow? Its the manufacturer defined limit of when to stop (likely in terms of voltage) charging. Also the percentage remaining is also an algorithm (batteries do not drop voltage linearly so it requires code to produce a guess of remaining capacity).
Furthermore, as pointed out by others the cell chemistry is optimized for the application (capacity, temperature range, material degradation, change speed, etc.) so they roll all this up into a 0..100% "number" that hides all the detail.
You probably already figure that out.....
Furthermore, as pointed out by others the cell chemistry is optimized for the application (capacity, temperature range, material degradation, change speed, etc.) so they roll all this up into a 0..100% "number" that hides all the detail.
You probably already figure that out.....
The same stuff does really apply. It's just that the economic and technical environment of cell phones is different, so the phone makers don't care. (or basically have a desire to have your battery degrade)
(1) Phone batteries get mistreated in about the worst possible ways. People just plug them in before they go to sleep, and they go up to 100% and sit there for several hours every. single. night. And you've probably seen how it's not too unusual for people to run their phones down until they shut themselves off. I'm sure they do have a little bit of margin/reserve there, but it's still at a level that's not good. Also, they have no temperature management, so they're going to get abused a little bit from hot and cold.
(2) How long should they last? As someone mentioned, people are so into the habit of replacing phones every couple of years, most people are just used to the expectation that the phone is going to be "bad" and replaced every other year, so some degraded battery just seems "normal" to them. And if people weren't quite deciding on their own to do it, that's where the phone manufacturers have a little bit of incentive to let the batteries get damaged to be bad within about 2 or 3 years so people will not want to keep their old phones for too long and want to buy a new one. It's WAY different with electric cars. People should be expecting that their car batteries should last longer than that, so you have the stronger recommendations of 10-90% or 20-80% to make them last longer.
(3) With phones or laptops, people aren't going to care that much if their battery gets worn out and needs replacing every couple of years because it's $15 or $40 and isn't that big a deal. They would prefer the tradeoff of using the full 100% of capacity in the battery, to get more practical use from the device, at the expense of shorter lifetime of the battery.
We had a Samsung netbook some years ago that included a setting for extended battery life to limit the charge level to 80%. That would be great for helping laptop batteries not die in a few years, but most laptops or cell phones don't have any setting to do that, which is a little unfortunate. So they go to 100%, which gives more running time, but shorter lifetime. I do try to manually do that for my cell phone. I don't keep it connected to charging all night. I'll charge it some at home in the morning while getting ready for work and at my desk at work so that I can stop it somewhere around 80-90% because I DO keep my cell phones generally longer than two years. But I also only ;buy phones with user replaceable batteries because I'll sometimes pay $10 or $15 to get a couple more years from my phone.
WannabeOwner
Well-Known Member
So having an e.g. one-hour timer on my phone charger would be better? [than plugging it in and forgetting about it / overnight]
It would still charge to 10)% but then immediately "drive" and the charge would fall.
maybe I could figure out current-percentage to 100% charge-time, and set the timer to give me 90%-ish
battery might be cheap [for me], phone might be traded in after a couple of years [probably not, in my case], but should I be assuming that The Planet is OK with that? or should I be making an effort?
It would still charge to 10)% but then immediately "drive" and the charge would fall.
maybe I could figure out current-percentage to 100% charge-time, and set the timer to give me 90%-ish
battery might be cheap [for me], phone might be traded in after a couple of years [probably not, in my case], but should I be assuming that The Planet is OK with that? or should I be making an effort?
Maybe get a very low power charger that would take longer to charge the phone? Maybe then you could leave it plugged in overnight but still not charge all the way. I may experiment with this...
You don't have to avoid charging to 100%. But be prepared to lose a third of capacity within 1-2 years of use.
If you want to prolong battery health, charge it for short periods daily. For example, you drop to 10-40%, plug it in.
As soon as you get to 80-90%, unplug. It's safe to charge more but don't keep it above 95% for hours and hours.
Worst thing to do is plug in overnight. It will charge to 100% within an hour and it will stay there for the whole night.
Discharging to 10-20% is fine. Just plug it in for a while as soon as you can.
Phone manufacturers want the best battery spec. They care little about longevity. Also, most smartphones are
replaced after 2 years so it's not as important as with cars.
For example, Samsung allows battery to be charged up to 4.40V. This is very high voltage. We, consumers,
can't change charging peak voltage. But we can unplug before reaching very high cell voltage. This will prolong
battery life considerably.
So, for daily usage, charge modestly. Going for weekend party, charge to 100%.
If you want to prolong battery health, charge it for short periods daily. For example, you drop to 10-40%, plug it in.
As soon as you get to 80-90%, unplug. It's safe to charge more but don't keep it above 95% for hours and hours.
Worst thing to do is plug in overnight. It will charge to 100% within an hour and it will stay there for the whole night.
Discharging to 10-20% is fine. Just plug it in for a while as soon as you can.
Phone manufacturers want the best battery spec. They care little about longevity. Also, most smartphones are
replaced after 2 years so it's not as important as with cars.
For example, Samsung allows battery to be charged up to 4.40V. This is very high voltage. We, consumers,
can't change charging peak voltage. But we can unplug before reaching very high cell voltage. This will prolong
battery life considerably.
So, for daily usage, charge modestly. Going for weekend party, charge to 100%.
I did find a 1A power supply and charged on that, was adding about 13% per hour. Still normally too much to leave it plugged in overnight, but better. I see a 0.5 amp source on Amazon cheap -- maybe I'll get one of those.Adding 50% overnight might work out, and the slower charge rate is probably a little easier on the battery, too.
WannabeOwner
Well-Known Member
I have been adopting this charging policy on my Power Tools. After using Garden Tools, or Electric Drills etc. (replaceable batteries) I charge for an hour (no idea how full that gets them, but it isn't 100%) and then when I want to use them I charge to full and immediately use. Over winter, when they are unused, I charge "for a bit" once a month so they don't run down and stay at "flat" for weeks on end.
But the batteries are so beefy, compared to my modest, occasional, use that its hard to tell if what I am doing is a waste of time - the TECH will move on before I have chucked the batteries away as being useless.
But the batteries are so beefy, compared to my modest, occasional, use that its hard to tell if what I am doing is a waste of time - the TECH will move on before I have chucked the batteries away as being useless.
Shock-On-T
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This!
Tesla could have set the 100% to be the battery voltage we currently get at 90%. We'd all be maxing at 90% and not know it.
Having said that, I'm sure that with the short lifespan of phones the manufacturer would rather focus on the short term and make it look like their phones had the longest possible run time, so would sacrifice the battery and let them charge as high as possible.
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