Battery/Device Charging

[TwiceHorn 30834]

So, as a long time user of portable devices (laptops, smartphones). I am a bit compulsive about plugging em in whenever a charger is available.  I use my laptop plugged in pretty much non-stop at home.  This is a relic of the days when a phone or laptop battery only provided a couple of hours of life and the risk of 0 was real.

Over the years, I haven't had any  examples of batteries going bad except when it was their time (after a couple of years with a phone, several years with a laptop).

I understand the risk of overcharging, but am of the understanding that most batteries/charging circuits have overcharge protection that's pretty effective and most of them indicate 0 current draw when fully charged and plugged in.

My understanding also is that battery life corresponds most directly to the number of charge cycles the battery undergoes.  I rarely if ever let a device get fully discharged or anywhere near it, so my cycles come as accumulations of partial discharge (5x20% or whatever), and thus accumulate slowly.

Thus, the recent advice to let your battery discharge more and leave devices unplugged confuses me. That seems to contribute to the ultimate death knell of batteries in charge cycles moreso than any real risk of overcharging and/or overheating.

I don't leave phone plugged in overnight, I do leave laptop plugged in the whole time I'm at home.  If I plan to road warrior, I prefer to leave with close to 100% charge.  My devices rarely/never get warm from charging or a combination of ambient conditions and charging.

The battery protection modes are enabled on most of my devices, if they have them, but they still often charge to 100% notwithstanding it says it will stop it at 80.

What the hell is going on here?

[RPM 26090]

[immamac 41616]

2 hours ago, TwiceHorn said:

So, as a long time user of portable devices (laptops, smartphones). I am a bit compulsive about plugging em in whenever a charger is available.  I use my laptop plugged in pretty much non-stop at home.  This is a relic of the days when a phone or laptop battery only provided a couple of hours of life and the risk of 0 was real.

Over the years, I haven't had any  examples of batteries going bad except when it was their time (after a couple of years with a phone, several years with a laptop).

I understand the risk of overcharging, but am of the understanding that most batteries/charging circuits have overcharge protection that's pretty effective and most of them indicate 0 current draw when fully charged and plugged in.

My understanding also is that battery life corresponds most directly to the number of charge cycles the battery undergoes.  I rarely if ever let a device get fully discharged or anywhere near it, so my cycles come as accumulations of partial discharge (5x20% or whatever), and thus accumulate slowly.

Thus, the recent advice to let your battery discharge more and leave devices unplugged confuses me. That seems to contribute to the ultimate death knell of batteries in charge cycles moreso than any real risk of overcharging and/or overheating.

I don't leave phone plugged in overnight, I do leave laptop plugged in the whole time I'm at home.  If I plan to road warrior, I prefer to leave with close to 100% charge.  My devices rarely/never get warm from charging or a combination of ambient conditions and charging.

The battery protection modes are enabled on most of my devices, if they have them, but they still often charge to 100% notwithstanding it says it will stop it at 80.

What the hell is going on here?

Battery degradation and cycles are most stressful to most modern battery chemistry (lifepo4, li-ion, etc) while charging to full from 85%+. The recent recommendation of cycling from 15-80% allows you to stay within the window of optimized charge current and voltage. (Fastest charging, minimal degradation, highest efficiency) 

Your battery staying topped up isn't bad for it per se it's just that it adds cycles regardless because it must allow the battery to discharge enough to charge it with a safe current. 

It's not hocus pocus and it's why most advanced or flagship devices will smart charge overnight where it charges slowly instead of quickly through the whole cycle. 

[Gil Bang 25551]

I've got a nice dell laptop (that's big and heavy, and old, but still great) and a cheap Chromebook.   I keep the battery out of the Dell, and just run it on the charger.  If I ever do need to take it with me, I figure I'll have good battery life. 

Chromebook battery is built in, so, when the life gets shitty, I get another cheap Chromebook.

[TwiceHorn 30834]

11 hours ago, immamac said:

Battery degradation and cycles are most stressful to most modern battery chemistry (lifepo4, li-ion, etc) while charging to full from 85%+. The recent recommendation of cycling from 15-80% allows you to stay within the window of optimized charge current and voltage. (Fastest charging, minimal degradation, highest efficiency) 

Your battery staying topped up isn't bad for it per se it's just that it adds cycles regardless because it must allow the battery to discharge enough to charge it with a safe current. 

It's not hocus pocus and it's why most advanced or flagship devices will smart charge overnight where it charges slowly instead of quickly through the whole cycle. 

I had not seen the explanation about topping up being bad before. I periodically see articles saying don't top up, but without much explanation why. 

Also I have a pixel phone that does adaptive charging and it seems comparatively slow. But that's ok. Again I had not seen the explanation before. 

Edited July 5 by TwiceHorn

[markstanco 12425]

My teens think leaving the house with 20% and no charger is perfectly fine. They also ride in the truck on long road trips with chargers available and when we get to the destination they are under 20% and complain.

Thats all I got.

[MonkeyDoughnut 9974]

Good explanation/analogy:

Here’s iFixit’s resident battery expert, Arthur Shi:

“In general, li-ion batteries don’t like to operate near max capacity. My go-to analogy is a sponge and a cup of water. The sponge represents the graphite anode and the water represents the lithium ions.

“When you charge a li-ion battery, the lithium ions have to embed into the graphite (intercalation). When a sponge is bone dry and you pour water onto it, it readily absorbs water. As it saturates, you have to slow down the water input, or water will start puddling on top of the sponge.”

But this last part is not only slower, it’s also the part that causes the most damage to the battery. 

“Imagine that the water that puddles on top solidifies irreversibly. This would reduce the mating surface area of the sponge and reduce the amount of water that can be recovered from the sponge,” says Shi. “For a li-ion battery, this is known as ‘lithium plating,’ which irreversibly reduces the battery capacity.”

Limiting the maximum charge gives a substantial increase to the overall life of a battery. If we measure the life of a battery not in cycles, but in the number of electrons it can deliver to your phone over its lifetime, then we’re looking at a possible increase of 400%. That is, your battery could deliver 4X the number of electrons. And yes, that means it could last up to four times as long, according to some simple testing:

“[C]harging to 80% instead of 100% multiplies by 4 the amount of energy the battery will have transferred to you over its life—the only tradeoff being to compromise on how much energy you can get out of a full charge (big slices, small cake VS small slices, large cake). This also means you can use your battery for 4 times longer before it gets to the end of its rated life,” “space mechatronics engineer” Mister Mystère wrote on Stack Exchange last year. 

[Parliament 13997]

On 7/4/2024 at 8:27 PM, markstanco said:

My teens think leaving the house with 20% and no charger is perfectly fine. They also ride in the truck on long road trips with chargers available and when we get to the destination they are under 20% and complain.

Thats all I got.

Young people are so dumb.

[freyguy 4239]

4 hours ago, MonkeyDoughnut said:

Good explanation/analogy:

Here’s iFixit’s resident battery expert, Arthur Shi:

“In general, li-ion batteries don’t like to operate near max capacity. My go-to analogy is a sponge and a cup of water. The sponge represents the graphite anode and the water represents the lithium ions.

“When you charge a li-ion battery, the lithium ions have to embed into the graphite (intercalation). When a sponge is bone dry and you pour water onto it, it readily absorbs water. As it saturates, you have to slow down the water input, or water will start puddling on top of the sponge.”

But this last part is not only slower, it’s also the part that causes the most damage to the battery. 

“Imagine that the water that puddles on top solidifies irreversibly. This would reduce the mating surface area of the sponge and reduce the amount of water that can be recovered from the sponge,” says Shi. “For a li-ion battery, this is known as ‘lithium plating,’ which irreversibly reduces the battery capacity.”

Limiting the maximum charge gives a substantial increase to the overall life of a battery. If we measure the life of a battery not in cycles, but in the number of electrons it can deliver to your phone over its lifetime, then we’re looking at a possible increase of 400%. That is, your battery could deliver 4X the number of electrons. And yes, that means it could last up to four times as long, according to some simple testing:

“[C]harging to 80% instead of 100% multiplies by 4 the amount of energy the battery will have transferred to you over its life—the only tradeoff being to compromise on how much energy you can get out of a full charge (big slices, small cake VS small slices, large cake). This also means you can use your battery for 4 times longer before it gets to the end of its rated life,” “space mechatronics engineer” Mister Mystère wrote on Stack Exchange last year. 

 

 

[52-80 18982]

Batteries don't like extreme high or low state of charge.  Favored resting SOC is at half-capacity or below.

On important devices with software control - laptops, phones - enable a 80% cap for regular use.  That way, it doesn't matter if you leave it plugged in. 

On other stuff like power tool batteries, after a use, if it's not around empty, just let it sit. Don't feel like you have to keep it always topped off and ready.

[Elvis 3348]

I have replaced two laptop batteries in my Dell XPS 13.  I have a docking station that powers the laptop and hooks me up to monitors and peripherials.  I don't really have a way to keep this thing under 80% charge.

The batteries don't fail in a way that affects their power performance.  They swell and I can see the case and keyboard swelling.  It's a pretty easy fix to crack the case and replace a battery for $45.

[52-80 18982]

On 7/15/2024 at 9:52 PM, Elvis said:

I have replaced two laptop batteries in my Dell XPS 13.  I have a docking station that powers the laptop and hooks me up to monitors and peripherials.  I don't really have a way to keep this thing under 80% charge.

https://www.dell.com/support/contents/en-us/article/product-support/self-support-knowledgebase/software-and-downloads/dell-power-manager