[Guide] The Care and Feeding of Lithium Polymer Batteries

[m0_onriver]

does this mean, if your phone drops to 40%, you have to charge it till 100%?

coz i've read a post from another forum, saying the sweet spot for lithium ion batt, is from 40-80%

 

[Cherrie Blossom]

When it told you to charge the battery, you plugged the charger in. When it was fully charged you used it, waiting to charge it again until you got the message to charge it again.

In most phones, that message comes at around 5%-10% of charge. Discharging a lithium battery that far will give you a lifetime of about 300-500 charges, but the battery will start losing capacity long before that.

Now you use the phone until it tells you to charge the battery, right? Wrong. Try to never (except, as you'll see later, during conditioning*) let the battery get below 40% charge. Letting it get below 50% is where the lifespan starts dropping. 40% won't shorten the life enough to matter. 20%? Half the life. 5%? The battery probably won't last a year.

If it's so harmful for the battery to be discharged past 40%, then why don't manufacturers make the "please charge" message at 40% rather than 5 or 10%? It seems that users are likely to be unaware of the batteries' vulnerabilities, so the only source of instructions/information they can get are from notifications or messages from the phone. If the messages are given at supposedly the "right point", according to what you claim, that is, at 40%, then users are more likely to abide it, avoid discharging past 40%, and charge it. At the end of the day, it isn't really the users' fault that batteries die so quickly - it's lack of/misleading information that's given to them. These issues can easily be avoided if users are given the appropriate information. If I didn't read this post, I wouldn't have known that discharging past 40% is unhealthy for the battery.

 

[Rukbat]

If it's so harmful for the battery to be discharged past 40%, then why don't manufacturers make the "please charge" message at 40% rather than 5 or 10%

Then they wouldn't be able to sell so many batteries (at inflated prices, compared to what distributors sell them for).

It seems that users are likely to be unaware of the batteries' vulnerabilities, so the only source of instructions/information they can get are from notifications or messages from the phone.

Or from researching lithium batteries on the web.

If the messages are given at supposedly the "right point", according to what you claim, that is, at 40%, then users are more likely to abide it, avoid discharging past 40%, and charge it.

Not really. I've had many people complain that they can't get through a day on 100% of the battery's capacity, so they definitely can't on 60% of its capacity, but they were going to get as much use out of the battery as they could (meaning discharging until the phone shut off). Then they complain when the battery dies (totally dead and unchargeable) after 3 months because they want it to keep going, full 100% to 0%, for the two years until they buy a new phone. (Which, of course, is unrealistic - but they don't want to hear that.)

At the end of the day, it isn't really the users' fault that batteries die so quickly

Not unless they've been told here or on some other site.

These issues can easily be avoided if users are given the appropriate information.

Remember, the world isn't run by "right" or "nice", it's run by "how much can I make, honestly or not?" The manufacturers don't care if you have to buy a new battery every month. Why do you think there are so many phones now that have non-removable batteries? It costs you $10 and a minute to replace a battery. You pay them $60 for that. That's another $50 in their pockets. (Actually more, since they don't pay retail for batteries. And why I haven't upgraded my phone in 4 years. My next phone will have a removable battery, the same as my current, over 4 year old one does. I'm just waiting for a flagship phone with a removable battery that can be rooted.)

 

[Mooncatt]

Then they wouldn't be able to sell so many batteries (at inflated prices, compared to what distributors sell them for).

I'll throw in another twist here.

Can you imagine the reaction from Mr. General Consumer with no battery knowledge, who's shiny new phone only goes for a few hours because of best charging practices? Consumers are mostly concerned with time between charges, not so much overall lifespan. This is, of course, in part due to the lack of info out there. Hence all the "I just charge it overnight because it's not hurting anything" posts I see.

I'm sure manufactures would allow over-charging and further discharge levels if the battery could handle it without blowing up or becoming a hazard, just to get that extra time between charges.

 

[Rukbat]

Oh, they probably would. But charging a lithium battery when it's fully charged gives you a Note 7, and I'm sure the cost/benefit ratio of exploding batteries is a bit too high for the manufacturers.

The problem is the use of the battery down to 0 - and we see posts like that all the time. Then the battery stops charging at 80%, or it only lasts for 4 hours between charges, or something else with an immediate impact on the user. I guess people are so used to things not working as advertised (if you're old enough, you remember when they did) that they just accept it as something they can't do anything about and they buy a new battery (or pay for one to be installed - it looks like user-removable batteries are on the way out) every few months. (I recently wondered if I was still getting the same life on my over-4-year-old battery. It seems to be about the same, but one day I might test it.)

 

[mwake4goten]

I'm finding this all very interesting. First real smartphone I fell in love with was HTC One M8, still use it as a backup. Did all the things that you shouldn't do if you want preserve the longevity of the battery due to ignorance. And within 12 months was having to charge my phone twice a day sometimes three.

Got the HTC 10 now, and to increase the longevity of my current phone I now employ all the battery saving tips and tricks. 18 months later still only charging my phone once a day.

I don't let my phone go to 0 percent before charging now like I used to do with my old phone. Most of the time as soon as it gets to 20 I put it on the charger. I know some say you shouldn't let it go lower than 40% but I find that too much of an inconvenience. I've been doing 20% and I've had no real problems. But regardless of the number I agree that letting it go to 0 percent all the time is a bad idea.

 

[Rukbat]

Very few phones can actually discharge a phone to totally dead - 0% charge. When a phone indicates 0%, the battery still has plenty of charge left.

Because if you dototally discharge a lithium battery to 0%, then charge it, it's likely to behave like a Note 7 (and explode).

But if you look at Cadex' discharge curves at Battery University - How to Prolong Lithium-based Batteries, you'll see that maximum life comes from recharging at 50%. I think that's a bit extreme too (although I did that with my V551 battery since 2004, and it's still giving me good time-between-charges - after 13 years). So I have GSam Battery Monitor set to give me alarms at 40% on the way down and 90% on the way up. We'll see how that goes. Accu​Battery would do a better job, but I'm not running a new enough version of Android for it to install.

 

[mumfoau]

Are iPhones and Androids inherently different? I never let my iPhones get low but charge them every night overnight. After 5-6 months with my iPhone XS the battery health was still at 100%. Though the iPhone and most Android phones now have sealed batteries, I only take this charging habit stuff into consideration when I'm using an Android device.

 

[Mooncatt]

Are iPhones and Androids inherently different? I never let my iPhones get low but charge them every night overnight. After 5-6 months with my iPhone XS the battery health was still at 100%. Though the iPhone and most Android phones now have sealed batteries, I only take this charging habit stuff into consideration when I'm using an Android device.

They both use Li-ion batteries, but it may be possible that Apple sources a different manufacturer with higher standards (Then again, there isn't many battery manufacturers in the first place). Or you could just be lucky. All these suggested practices are based on averages, so some people will do better and others will do worse.

 

[mumfoau]

They both use Li-ion batteries, but it may be possible that Apple sources a different manufacturer with higher standards (Then again, there isn't many battery manufacturers in the first place). Or you could just be lucky. All these suggested practices are based on averages, so some people will do better and others will do worse.

Maybe it is, in fact, an Apple thing. I've charged all my iPhones that way and since the introduction of the battery health in settings, it had never dropped below what it was when I got the phone.

The alternative is that it's lying to me after all the negative press about slowing phones down lol

 

[mmmms123]

Hi,thank you so much for this post, i learned alot of new things about batteries now, but there was 1 part which was not clear for me. The conditioning stage. Now I plan to get Galaxy S10, and with taxes just the 128gb version gets over $1100 in my country. And that amount is definetily not low for me. So i plan to keep it for 3-5 years. And my biggest concern is ofcourse the battery.
So i will tell what i should do step by step, and please give me feedback if i understood it correctly.
1I go to store get the phone bring it home
2without using it i just put it to charge and wait till it gets to 100% and phone says that its charged, i wait extra 30 minutes.
3 I use the phone until its literally dead. Like 0% and phone turns off. I let it charge 100%+30 min again.
4 I do this 3 times.
And after finishing 3rd time, when i put it to charge i just dont put it till 100%. i put it till 94%. And starting from that date, i never let it discharge below 40%. Did i get it correctly?

And one more thing.
My work is a kind of work which doesnt have fixed time. And i dont have the opportunity to charge when i'm at work. So by any chance, if i let it below 40, 30% just 2-3 times, will it hurt the battery? Again, as i said i will do my best not to get below 40% but you never know.
Thank you for your time!

 

[anon(10181084)]

I was actually able to, after I learned about this stuff, keep one of my previous phones (Cat S41) charged after 40% most of the time. But now with a puny 3000mAh battery and an ever worsening Android device addiction pretty uch the only device that gets its battery treated properly is my laptop (most of the time I charge at 35%) and the battery is like brand new after a few months.

 

[Mooncatt]

Leo Laporte (a radio tech advise host) just released a podcast on this topic, pretty much saying the same thing we have.

https://twit.tv/shows/ask-the-tech-guy/episodes/15?autostart=false

 

[Mooncatt]

I'm finally forced into using a phone with a sealed battery, so I decided to do a little testing. The battery is 4,000 mAh, and using a Quick Charge capable charger will allow for up to 3,400 mA. That's technically lower than the 1C rate that most Li-ion batteries are able to handle, but I decided to also try a standard, non-quick charging, charger to see how battery temps are affected. The charge rate averages around 1,200-1,500 mA depending on what I'm doing on the phone. I noticed that allowed the battery to run about 10-15°F cooler during charging.

With quick charging, it runs about 107°F, which is fairly warm when it comes to risking long term damage. With standard charging, it's been 92-97°F, which is more protective against damage. Sure it takes a lot longer to charge, but I have access to a charger most of the time. If I do need a quick boost, I'll use the Quick Charge, but I mostly try to stick with basic charging now.

I'm curious if anyone else has gone this route now as well.