# Where can I get proof of the battery rule **URL:** \ **Category:** Factual Questions\ **Created:** [May 8, 2017, 12:29pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119 "2017-05-08T12:29:14Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Long\_D](https://avatars.discourse-cdn.com/v4/letter/l/cdc98d/32.png) [@Long\_D](https://boards.straightdope.com/u/Long_D)\ **Post date:** [May 8, 2017, 12:29pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/1 "2017-05-08T12:29:14Z")
I have asked this question before but cannot find scientific papers that prove it’s theories. Please lead me to an individual with a scientific/electronic background that will let me know what rules of cell phone LI ion battery use are the most efficient. Thanks. ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [May 8, 2017, 12:44pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/2 "2017-05-08T12:44:42Z")
Plug it in when it gets low. What? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 8, 2017, 12:54pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/3 "2017-05-08T12:54:23Z")
What rule are you asking about? ---
**Author:** ![Crane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crane/32/3495_2.png) [@Crane](https://boards.straightdope.com/u/Crane)\ **Post date:** [May 8, 2017, 12:59pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/4 "2017-05-08T12:59:19Z")
Are you asking about text and data vs voice or…? ---
**Author:** ![Long\_D](https://avatars.discourse-cdn.com/v4/letter/l/cdc98d/32.png) [@Long\_D](https://boards.straightdope.com/u/Long_D)\ **Post date:** [May 8, 2017, 1:25pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/5 "2017-05-08T13:25:30Z")
I am speaking about the rules regarding power and battery life. Such as the 80%-40% rule and keeping it charged at these levels to get the most out of your LI ION battery life. ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [May 8, 2017, 1:32pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/6 "2017-05-08T13:32:52Z")
I think he wants to know exactly what he can do to make his cell phone battery last longer. And he wants proof. Naturally, [wikipedia](https://en.wikipedia.org/wiki/Lithium-ion_battery#Battery_life) cites proof, such as : [Research & Development World](http://www.rdmag.com/article/2014/04/trace-degradation-analysis-lithium-ion-battery-components) and [Temperature dependent ageing mechanisms in Lithium-ion batteries – A Post-Mortem study - ScienceDirect](http://www.sciencedirect.com/science/article/pii/S0378775314004352) TLDR, there are 2 forms of loss : calendar loss and cycling loss. Calendar loss happens no matter what you do. Charging the battery up more (over about 80%) greatly accelerates the rate it loses capacity. It can lose 1% a month or more. Discharging the battery below 20% also greatly accelerates the capacity loss. Cycling loss happens every time you discharge the battery and then charge it up again. You get roughly 1500 cycles tops for the type of cell chemistry a cell phone battery uses (often less) before the battery is shot. So you cannot win. If you leave the phone on the charger all the time, it will keep the battery at 100%, and you are losing about 1% of the max capacity every month. So after 3 years, you are down to 2/3, and basically it’s toast. (it will degrade more and more rapidly from there) If you take the phone off the charger before 100%, it will begin to discharge. If you use it some, it’s discharging. This is a cycle because you are going to have to recharge it now. Do this for 3-5 years, and the battery will be toast. Look, a new battery is $30. How much does your phone plan cost? Having a cell phone with an active plan is costing you _far_ more per month than a once in 3 years replacement of the battery will cost. Basically, every month, that future battery replacement is cost you about $1 ($36 new battery with the tiny screwdrivers you need/36 months) while the phone plan is cost you at \*least \*$40 a month. The phone itself will be trash in 3-6 years. You can keep using old phones for a while, but eventually you will be unable to use any recently published apps, and the existing apps will be unusably slow. Replacing the whole phone is going to cost $150-$650, depending on how nice a new phone you want. \*That’s \*what costs ya. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 8, 2017, 1:44pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/7 "2017-05-08T13:44:27Z")
We’ve already answered your question. But, you might want to review some of the literature on the web: > **[Li-Ion BMS - White Papers](http://liionbms.com/php/white_papers.php)** > > White Papers: Exploring issues relating to Li-Ion cells and batteries. > **[Lead-acid-white-paper.pdf](https://www.batterypoweronline.com/wp-content/uploads/2012/07/Lead-acid-white-paper.pdf)** > > 594.84 KB [https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=37&ved=0ahUKEwjO74fctuDTAhXsx1QKHZIaBKI4HhAWCEYwBg&url=http%3A%2F%2Fpdfstream.manualsonline.com%2F1%2F1e28404c-b0e2-4cfb-a1d6-6daaeff71692.pdf&usg=AFQjCNFCAt5wkL89RH5kLo-LqC9PXqTtgg](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=37&ved=0ahUKEwjO74fctuDTAhXsx1QKHZIaBKI4HhAWCEYwBg&url=http%3A%2F%2Fpdfstream.manualsonline.com%2F1%2F1e28404c-b0e2-4cfb-a1d6-6daaeff71692.pdf&usg=AFQjCNFCAt5wkL89RH5kLo-LqC9PXqTtgg) ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [May 8, 2017, 1:54pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/8 "2017-05-08T13:54:46Z")
> [@SamuelA](#): > > Look, a new battery is $30. IME, batteries are $10-15, or they have to be replaced by a tech for $50 or more. But you’re right. If you’re going to keep an older phone, just plan on a new battery every two years or so to keep the charging times down and capacity up. And just use/charge the phone whatever way works best for you, since it doesn’t really matter in the end. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 8, 2017, 2:12pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/9 "2017-05-08T14:12:41Z")
Are batteries standard enough that you can buy a replacement battery for a two-year-old phone? ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [May 8, 2017, 2:14pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/10 "2017-05-08T14:14:18Z")
> [@Amateur\_Barbarian](#): > > IME, batteries are $10-15, or they have to be replaced by a tech for $50 or more. I was talking about genuine OEM batteries. You do not want to put a $10 knockoff battery in a phone if you don’t want to run the risk of a fire. ---
**Author:** ![SamuelA](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@SamuelA](https://boards.straightdope.com/u/SamuelA)\ **Post date:** [May 8, 2017, 2:15pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/11 "2017-05-08T14:15:18Z")
> [@Chronos](#): > > Are batteries standard enough that you can buy a replacement battery for a two-year-old phone? Yes and no. No, they aren’t standard. In today’s globalized world, though, that doesn’t matter - you will be able to order the exact battery you need online from somewhere. ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [May 8, 2017, 2:17pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/12 "2017-05-08T14:17:36Z")
> [@SamuelA](#): > > I was talking about genuine OEM batteries. You do not want to put a $10 knockoff battery in a phone if you don’t want to run the risk of a fire. I’ve had no problem with Anker products, nor do I know of any reports of problems with their goods. I’m sure there are no-name batts out there that lack proper charging protection and so forth, yes. ---
**Author:** ![DrCube](https://avatars.discourse-cdn.com/v4/letter/d/a3d4f5/32.png) [@DrCube](https://boards.straightdope.com/u/DrCube)\ **Post date:** [May 8, 2017, 5:08pm UTC](https://boards.straightdope.com/t/where-can-i-get-proof-of-the-battery-rule/786119/13 "2017-05-08T17:08:17Z")
> [@SamuelA](#): > > I was talking about genuine OEM batteries. You do not want to put a $10 knockoff battery in a phone if you don’t want to run the risk of a fire. Seconded. A couple of years ago, instead of buying one $90 laptop battery from the OEM site, I went on Amazon and bought two from China for $45. One of them didn’t work at all and the other burned up and destroyed my laptop. Don’t go cheap on batteries!