Battery life: leave plugged in or let discharge

[Readirect]

Originally Posted by rashkae

Neither. Best practice for storage of LiOn batteries is to do so between 40-60% charge. Either leaving it fully charged at 100% or letting it run flat will be stressful to the battery.

If the Kobo is turned off, it should be able to maintain a storage charge for a *long* time. Unfortunately, there is no way to power off Kindles, so they will run down and need periodic charging. Although so far, all the readers I have let run flat, Kindles and Kobo's, have successfully powered themselves off when battery is low enough to prevent any immediate battery killing damage, (in truth, no sane LiOn powered device should ever allow you to actually run battery completely empty.)

It is ABSOLUTELY FALSE that keeping a lithium-based battery at 100% will damage it. That's because ALL such batteries have a mechanism which turns off the charging once it becomes fully charged.

Here's a YouTube video from Dell which says just that (@ 1:20 of the video). It deals with laptops but it applies to all battery-powered electronics devices.
https://www.youtube.com/watch?v=aF6kfMsQxdQ

FWIW, that's a myth left-over from the last-gen batteries which where nickel-based.

[DNSB]

Originally Posted by Readirect

It is ABSOLUTELY FALSE that keeping a lithium-based battery at 100% will damage it. That's because ALL such batteries have a mechanism which turns off the charging once it becomes fully charged.

Here's a YouTube video from Dell which says just that (@ 1:20 of the video). It deals with laptops but it applies to all battery-powered electronics devices.
https://www.youtube.com/watch?v=aF6kfMsQxdQ

FWIW, that's a myth left-over from the last-gen batteries which where nickel-based.

Interesting since the default settings for longest battery life on my Lenovo laptop stops charging at 96%. The battery is a lithium ion polymer battery.

Currently hovering over the battery shows: 97% available (plugged in, not charging).

[Readirect]

Originally Posted by frostschutz

letting it turn itself off is not an option? it's in the power saving settings.

oh, I forget the max setting is 60 minutes... should be 1-2-3-7 days I guess

I would not keep it on a charger. Even if that worked, you never know. The charger might blow at some point, burn down your house, or fry the reader during a lightning storm, and it will just add to your electricity bill

With all due respect, everything you just stated is absurd. "Blowing up"?? "lightning storm"?? "electric bill"?? No, it's not gonna blow up ... the battery stops charging when it reaches 100%. That's pretty much why we're talking pennies per month for a plugged-in device that's unused. "Lightning"?? NO one should worry about that.

Whew.

[DNSB]

Originally Posted by Readirect

"Lightning"?? NO one should worry about that.
Whew.

Worrying about lightning depends on where you live. One of my relatives retired to Florida and has lost computers plus televisions/stoves/etc. twice due to lightning in the last 6 years. Her interior of her home now looks like an advertisement for surge suppressors and and the exterior is decorated in lightning rods.

[davidfor]

Originally Posted by Readirect

It is ABSOLUTELY FALSE that keeping a lithium-based battery at 100% will damage it. That's because ALL such batteries have a mechanism which turns off the charging once it becomes fully charged.

Here's a YouTube video from Dell which says just that (@ 1:20 of the video). It deals with laptops but it applies to all battery-powered electronics devices.
https://www.youtube.com/watch?v=aF6kfMsQxdQ

At 1:20 in that video, it starts discussing whether it is safe to leave the power plugged in. That has nothing to with what happens to the battery at different charge levels. In fact, there is nothing in that video about extending the overall life of the battery.

Now, you are correct, having a Li-Ion battery at 100% does not damage it. But, it can lead to an overall shorter life. And as you are pointing to laptop behaviour, a large number have a feature to stop charging at 70 or 80%. This is a battery saver function.

The 40% figure comes from the Battery University site. Specifically, this page. Which contains lots of details about how to treat Li-Ion batteries to make them last longer and why. But, a basic thing is that the more time a Li-Ion battery spends at the extremes of the charge level, the shorter the overall life.

FWIW, that's a myth left-over from the last-gen batteries which where nickel-based.

No, the recommendations for handling Nickel-based batteries are different. The rule that carried over from NiCads was that the batteries needed to be fully cycled and not partially charged. This is not so with Li-Ion. The recommendation for Nickel-based batteries from the above site is the same as for Li-Ion, but doesn't really state there are issues if stored at other charge levels.

Having said that, overall, I agree with that video for treating Li-Ion batteries, especially in laptop. There things you can do to extend the life, but, they don't really have enough effect to worry about. Just use the battery as you need to, and charge it when you can.

[rashkae]

Originally Posted by Readirect

FWIW, that's a myth left-over from the last-gen batteries which where nickel-based.

I already addressed this last time you said the same thing, including a link to some very technical citations. You're pounding the podium like a todler

[hollowpoint]

Common-sense suggestions in this article which are a summary, with supporting links, of the best practices for maintaining LIon battery life:

https://www.pcmag.com/news/357987/ch...myths-debunked

[Deskisamess]

I'll float my reasons for not wanting to leave my iPhone plugged in all night...have you ever tried to answer a cell phone, in the middle of the night in a dark bedroom, when it's plugged in? I'm legally blind without my glasses, and I don't want to have to struggle to answer an emergency call in the middle of the night, on a phone that is plugged in.

I always unplug it when I'm done reading for the night.

Our iPads are usually left plugged in over night. It's never been a problem.

[davidfor]

Originally Posted by hollowpoint

Common-sense suggestions in this article which are a summary, with supporting links, of the best practices for maintaining LIon battery life:

https://www.pcmag.com/news/357987/ch...myths-debunked

Sorry, that article is wrong. I didn't read past the first suggestion because it was absolute crap.

You should not trickle charge Li-Ion batteries. If you do, it is dangerous. And by dangerous, I mean potentially explosive. They get charged to full, then the charger turns off. They will not charge again until the battery charge drops below a certain charge level.

And just to be clear, "trickle charging" is used to keep a batteries charge level at 100% by maintaining a low charging current to the battery. This is used for some battery chemistries. But not Li-Ion.

[hollowpoint]

Originally Posted by davidfor

Sorry, that article is wrong. I didn't read past the first suggestion because it was absolute crap.

You should not trickle charge Li-Ion batteries. If you do, it is dangerous. And by dangerous, I mean potentially explosive. They get charged to full, then the charger turns off. They will not charge again until the battery charge drops below a certain charge level.

And just to be clear, "trickle charging" is used to keep a batteries charge level at 100% by maintaining a low charging current to the battery. This is used for some battery chemistries. But not Li-Ion.

Maybe you should have read a little farther, it does NOT recommend trickle-charging as a best practice. Instead, it was saying that smart protection built into phones makes this not a big deal, but that it's best NOT to trickle-charge:

The best thing to do: Don't worry about this too much. Plug the phone in (or place on the wireless charger) when you go to sleep; if you wake up sometime in the night, unplug it/move it to prevent constant trickle-charging. If you don't wake much, plug your phone into a smart plug that's on a schedule so it turns off.

Which is consistent with the trickle-charge recommendation at Battery University:
https://batteryuniversity.com/index...._ion_batteries

[johnwhelan]

My understanding based on the chemistry of the batteries is to maintain the maximum battery life for lithium batteries if you know you won't be using the device the battery should be stored at 40% charge which in reality means 50%-60% charge and just check the charge level every couple of months.
I have a couple of Nexus 7 devices that I use as ereaders but I only use one at a time. The other two are not used daily but are maintained in this way. They are elderly these days.

I've just picked up a couple of refurbished Kobo arc HDs which have a very nice screen display and they will be "stored" in the same manner. A lot cheaper than the equivalent new device.

Having said that keeping the device fully charged or plugged in will probably do less harm than letting it drain completely.

Ni Cad batteries should be fully discharged and recharged every six months or so to avoid the memory effect. Oral B still recommend this practice on their electric toothbrushes.

The Dell video does not talk about how best to prolong battery life if you aren't using the device. I suspect they would prefer you to just buy a new battery from Dell.

Cheerio John

B.Sc. Chemistry.

[DNSB]

content deleted for politeness.

[meeera]

Originally Posted by DNSB

Worrying about lightning depends on where you live. One of my relatives retired to Florida and has lost computers plus televisions/stoves/etc. twice due to lightning in the last 6 years.

Yes, I've lost a television and a couple of modems to lightning strikes. When a big storm's coming I disconnect devices like my laptop and phone.