Laptop battery use query

searchlight123

i use my windows 10 HP envy laptop for a couple of hours each morning. i do not move around with it. i tend to use it on battery and recharge as and when needed, but i read somewhere that if possible you should use a laptop plugged into the mains whenever you can.

is this correct? i have no problem having it plugged in, i just assumed it would not be good for the overall life of the battery to always be on charge (the battery is not one you can just unclip and remove).

anyone that can clarify this for me please?

many thanks.

esuhl

It's not good to keep the battery at 100% of charge all the time -- that's when it degrades the quickest.

Also, charging a battery at less than 30% degrades the cells more than at higher charges.

So... Ideally you want to keep the charge between about 30% and 65%.

(N.B. This assumes that you're using lithium-ion cells).

Strider590

esuhl wrote: »

It's not good to keep the battery at 100% of charge all the time -- that's when it degrades the quickest.

That's something of an urban myth, because the charging circuit doesn't let the cells get to a true "100%".

They use a stack of standard 18650 cells, which have a voltage range from 3.5v to 4.2v and so typically they'll got go much above 4.1v per cell or below 3.6 and they'll treat this as their 100% charge range.

More importantly there have been a number of people who have kept 18650 cells at maximum charge for 5+ years and found only a VERY small capacity loss.

There has always been BS and myth surrounding batteries, mythbusters tackled the old myth of keeping batteries in a fridge, something my parents told me years ago. I suspect somebody was told not to store them at high temperatures and went a little too far with it, someone asked why he/she had batteries in the fridge and it spread like wildfire.

The lithium battery myths are different, but they have probably been born out of their early use in mobile phones and the countless early incidents of the things going up in flames.


What definitely does damage lithium cells, is repeated heavy loads and repeated charge cycles.

http://industrial.panasonic.com/cdbs/www-data/pdf2/ACA4000/ACA4000CE254.pdf

Notice Samsung specifically graph the life cycle characteristics as capacity versus charge cycle count.

esuhl

Strider590 wrote: »

That's something of an urban myth, because the charging circuit doesn't let the cells get to a true "100%".

They use a stack of standard 18650 cells, which have a voltage range from 3.5v to 4.2v and so typically they'll got go much above 4.1v per cell or below 3.6 and they'll treat this as their 100% charge range.

Sure, but the higher the charge in the cells, the more degradation they'll suffer when being topped-up further.

Strider590 wrote: »

There has always been BS and myth surrounding batteries, mythbusters tackled the old myth of keeping batteries in a fridge, something my parents told me years ago. I suspect somebody was told not to store them at high temperatures and went a little too far with it, someone asked why he/she had batteries in the fridge and it spread like wildfire.

Interesting. According to a study I read on the Battery University site a long time ago, Li-ion cells degrade less rapidly at lower temperatures and if they aren't fully charged. Obviously you also don't want to let the charge drop so low that they can't safely be recharged. The recommendation was that they be stored at about 40% charge level in the fridge.

I can't find that article now (as it was years ago that I read it), but there's some similar info here. Make of it what you will.

http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

http://batteryuniversity.com/learn/article/how_to_store_batteries

http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

Strider590

esuhl wrote: »

The recommendation was that they be stored at about 40% charge level in the fridge.

You don't want to be doing that, it was an old myth said about standard alkaline batteries and it really was a myth.

What happens when you take things out of a fridge? What happens to the glass when you pour yourself a nice cold beer?
Dew point condensation..........

You really don't want condensation forming on/in your device, or even just on the battery terminals, this is a sure way to reduce it's life expectancy.

One of the other myths I hear is that batteries have to be cycled from fully charged to fully discharged and never top up charged, otherwise they develop "memory effect".
This came from early Ni-CD cells and doesn't apply at all to modern lithium based cells, unfortunately myths like this persist because the older generation doesn't understand the newer technologies, all they know is non-rechargable versus rechargable.

spud17

Strider590 wrote: »

You don't want to be doing that, it was an old myth said about standard alkaline batteries and it really was a myth.

What happens when you take things out of a fridge? What happens to the glass when you pour yourself a nice cold beer?
Dew point condensation..........

You really don't want condensation forming on/in your device, or even just on the battery terminals, this is a sure way to reduce it's life expectancy.

One of the other myths I hear is that batteries have to be cycled from fully charged to fully discharged and never top up charged, otherwise they develop "memory effect".
This came from early Ni-CD cells and doesn't apply at all to modern lithium based cells, unfortunately myths like this persist because the older generation doesn't understand the newer technologies, all they know is non-rechargable versus rechargable.

Resent this assumption.:)
I'm the old git that had to tell the youngsters at work that they shouldn't run Li-ion batteries in the power tools until they were completely flat, they mistakenly thought there was a "memory effect".

esuhl

Strider590 wrote: »

You don't want to be doing that, it was an old myth said about standard alkaline batteries and it really was a myth.

What happens when you take things out of a fridge? What happens to the glass when you pour yourself a nice cold beer?
Dew point condensation..........

You really don't want condensation forming on/in your device, or even just on the battery terminals, this is a sure way to reduce it's life expectancy.

Is that really much of an issue? I've never noticed any condensation forming on them. And I guess you could avoid that problem by putting them in airtight bags.

You shouldn't use batteries straight from the fridge anyway as discharging them will cause faster degradation than at room temperature.

I'd never heard of storing alkaline batteries in the fridge. I'm just going on the performance testing that was done by Battery University... and the other articles I've read that say that it's better to store Li-ion cells at low temperatures (but definitely above freezing!).

The Wikipedia entry for "Lithium-ion battery" says the following, although I note the citation issue:

Degradation is strongly temperature-dependent; increasing if stored or used at higher temperatures. High charge levels and elevated temperatures (whether from charging or ambient air) hasten capacity loss.[92] Carbon anodes generate heat when in use. Batteries may be refrigerated to reduce temperature effects.[133]I][URL="https://en.wikipedia.org/wiki/Wikipedia:Verifiability"]not in citation given[/URL][/I

https://en.wikipedia.org/wiki/Lithium-ion_battery

How To Geek recommend that you don't store Li-ion cells in the fridge due to the possibility of them being frozen by mistake or of condensation damage (which seem easily avoidable), but they do say that it will prolong the life of the battery.

http://www.howtogeek.com/179486/ask-htg-should-i-store-my-batteries-in-the-fridge/

agrinnall

I generally use my Lenovo Yoga 2 Pro with it plugged into the mains, but occasionally it displays a message to the effect that constantly running above 70% charge is not good for it and that it should be allowed to discharge to below that figure. I don't know whether that's just Lenovo BS but when I get the message I do run it off the battery for a while.

esuhl

agrinnall wrote: »

I generally use my Lenovo Yoga 2 Pro with it plugged into the mains, but occasionally it displays a message to the effect that constantly running above 70% charge is not good for it and that it should be allowed to discharge to below that figure. I don't know whether that's just Lenovo BS but when I get the message I do run it off the battery for a while.

It's best to keep the charge between about 30% and 65% (give or take). Running with the battery at 100% all the time will cause it to degrade quicker.

It's the same for all lithium-ion (Li-ion) batteries.

forgotmyname

When i bought the little one a laptop, i gave strict instructions to not leave the battery at 100% and to run it down every now and then. Ignore me and now the battery lasts just long enough for it to startup and before you can actually log in it says battery low and shuts down.

Running on mains all the time with a 100% full battery does kill the battery.

80% is a good state of charge to store them though. Put it away at 80% charge and in check it after 1 year it will still be close to that figure.

If your on mains and the battery is more than 80% take it out or run on battery first and then recharge to about 80%.

agrinnall

esuhl wrote: »

It's best to keep the charge between about 30% and 65% (give or take). Running with the battery at 100% all the time will cause it to degrade quicker.

It's the same for all lithium-ion (Li-ion) batteries.

You may be right, and perhaps that's why they give the warning at a 70% level, but there's no consensus in this thread to convince me one way or the other I'm afraid.