Re: [SLUG] Question on lithium ion batteries.
On 24/01/15 13:41, James Linder wrote: On 24 Jan 2015, at 9:00 am, slug-requ...@slug.org.au wrote: So, having absorbed, from my friends, the dangers of partially recharging a lithium-ion battery due to “memory”, I read the insert that came with the new laptop battery: – “Recharging a partially charged lithium-ion does not cause harm because there is no memory. Short battery life is mainly caused by heat rather than charge/discharge patterns.” Terry Pratchett: He does know Big Words after all he is a dealer … Battery Technology is VERY complex, so either you become a guru or you believe the manufacturer. lithium-ion is complex enough that I cannot believe that a manufacturer would make a charger that does not do the right thing. (lithium-ion-phosphate may NEVER be flattened, so even more complex) Battery manufacturers primarily compete on capacity on the date of purchase. If the battery lasts 18 months instead of 2 years most of the time the short lived cell isn't going to be held against the manufacturer. Discharging any lithium chemistry cell to 0 volts will pretty much destroy it. The only severe rule for mortals is to never charge A sort batteries with a B sort charger the consequences are fire and explosion. I opine that you may use the laptop permenantly 'on charge’ yet I have seen a disportionate number of dead laptop batteries contradicting what I say above. General Rule #1: Every time you flattern a battery you use up a percentage of it’s life. The ideal charger would keep the batteries at 99% charged allowing you to always charge (not 100% because the 100% level is temperature dependant and you don’t want to go to 101% because the day warmed or cooled) So if you have bought a system with a lessor charger you will buy batteries, the more you play the better the battery life, but like death and taxes dead battries. James I have seen some phones and laptops (very rare) that won't charge if the battery is above 90something %, those ones you could leave on charge without damaging them. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Question on lithium ion batteries.
On 24 Jan 2015, at 9:00 am, slug-requ...@slug.org.au wrote: So, having absorbed, from my friends, the dangers of partially recharging a lithium-ion battery due to “memory”, I read the insert that came with the new laptop battery: – “Recharging a partially charged lithium-ion does not cause harm because there is no memory. Short battery life is mainly caused by heat rather than charge/discharge patterns.” Terry Pratchett: He does know Big Words after all he is a dealer … Battery Technology is VERY complex, so either you become a guru or you believe the manufacturer. lithium-ion is complex enough that I cannot believe that a manufacturer would make a charger that does not do the right thing. (lithium-ion-phosphate may NEVER be flattened, so even more complex) The only severe rule for mortals is to never charge A sort batteries with a B sort charger the consequences are fire and explosion. I opine that you may use the laptop permenantly 'on charge’ yet I have seen a disportionate number of dead laptop batteries contradicting what I say above. General Rule #1: Every time you flattern a battery you use up a percentage of it’s life. The ideal charger would keep the batteries at 99% charged allowing you to always charge (not 100% because the 100% level is temperature dependant and you don’t want to go to 101% because the day warmed or cooled) So if you have bought a system with a lessor charger you will buy batteries, the more you play the better the battery life, but like death and taxes dead battries. James -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Question on lithium ion batteries.
over discharging will cause damage over charging will also cause damage (but less so) If the laptop is going to sit on your desk plugged into power for 90% of its life, run the battery down a bit (like to 50% charge), then turn the laptop off and take the battery out (assuming you want it to last when you go on the road), Once every few months, charge it up, run it down to about 20%, charge it again, then run it back down to 50% and take it out. Leaving the thing on charge all the time will generally kill it. The more you discharge the battery the less lifespan it will have, so if you can charge it at 50% all the time (assuming you are a regular user of said battery) it'll last longer than if you discharge it to flat every time. I reckon with modern batteries 30% charge is probably a good cutoff point in terms of cycle life vs calendar life. Every once in a while running it down to flat or nearly so then charging again isn't a bad thing, it'll slightly increase the capacity (this is a real effect, we see it on unpackaged lipoly cells we use in robots, its not the memory effect, its something else, but a cell thats been sitting for a while or only lightly used will gain ~30% capacity with some exercise) and more importantly let the fancy chips in the battery re-calibrate their calculation of the capacity of the battery. generally discharging or charging cause damage, but the damage gets worse the further from the middle you go, when they want a really long life from cells, they run them just around the middle range, like from 40% charge to 80% charge, with consumer lithium cells you will generally hit calendar life issues before cycle life if you don't go nuts. btw the memory effect is a specific thing for nicad cells that was discovered when the batteries were discharged to *exactly* the same point over and over again (say 20% state of charge), then when expected to discharge past that point they had practically no remaining capacity. http://en.wikipedia.org/wiki/Memory_effect#True_memory_effect On 23/01/15 18:15, William Bennett wrote: Menno, Thanks for the information. I will add this: you'd be surprised how many computer experts, professionals included, labouring under this misapprehension. I asked around because I had been told of the existence of “memory”, but felt that the manufacturers should know what they were talking about. William. On Fri, Jan 23, 2015 at 4:42 PM, William Bennett wrbennet...@gmail.com wrote: So, having absorbed, from my friends, the dangers of partially recharging a lithium-ion battery due to “memory”, I read the insert that came with the new laptop battery: – “Recharging a partially charged lithium-ion does not cause harm because there is no memory. Short battery life is mainly caused by heat rather than charge/discharge patterns.” Um, who's right? William Bennett, Armidale. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Question on lithium ion batteries.
I should probably add, Really new, and perhaps better quality laptops /may/ have better charge circuits, that won't try and charge a 95% charged battery again, thus saving it from the early death suffered from leaving the battery in a wall powered laptop. Generally speaking you should expect ~30% battery capacity loss after a year, and ~50% or more after 2 years in a battery that has been looked after but still used, better quality cells will fair better than this. On 24/01/15 01:44, Jake Anderson wrote: over discharging will cause damage over charging will also cause damage (but less so) If the laptop is going to sit on your desk plugged into power for 90% of its life, run the battery down a bit (like to 50% charge), then turn the laptop off and take the battery out (assuming you want it to last when you go on the road), Once every few months, charge it up, run it down to about 20%, charge it again, then run it back down to 50% and take it out. Leaving the thing on charge all the time will generally kill it. The more you discharge the battery the less lifespan it will have, so if you can charge it at 50% all the time (assuming you are a regular user of said battery) it'll last longer than if you discharge it to flat every time. I reckon with modern batteries 30% charge is probably a good cutoff point in terms of cycle life vs calendar life. Every once in a while running it down to flat or nearly so then charging again isn't a bad thing, it'll slightly increase the capacity (this is a real effect, we see it on unpackaged lipoly cells we use in robots, its not the memory effect, its something else, but a cell thats been sitting for a while or only lightly used will gain ~30% capacity with some exercise) and more importantly let the fancy chips in the battery re-calibrate their calculation of the capacity of the battery. generally discharging or charging cause damage, but the damage gets worse the further from the middle you go, when they want a really long life from cells, they run them just around the middle range, like from 40% charge to 80% charge, with consumer lithium cells you will generally hit calendar life issues before cycle life if you don't go nuts. btw the memory effect is a specific thing for nicad cells that was discovered when the batteries were discharged to *exactly* the same point over and over again (say 20% state of charge), then when expected to discharge past that point they had practically no remaining capacity. http://en.wikipedia.org/wiki/Memory_effect#True_memory_effect On 23/01/15 18:15, William Bennett wrote: Menno, Thanks for the information. I will add this: you'd be surprised how many computer experts, professionals included, labouring under this misapprehension. I asked around because I had been told of the existence of “memory”, but felt that the manufacturers should know what they were talking about. William. On Fri, Jan 23, 2015 at 4:42 PM, William Bennett wrbennet...@gmail.com wrote: So, having absorbed, from my friends, the dangers of partially recharging a lithium-ion battery due to “memory”, I read the insert that came with the new laptop battery: – “Recharging a partially charged lithium-ion does not cause harm because there is no memory. Short battery life is mainly caused by heat rather than charge/discharge patterns.” Um, who's right? William Bennett, Armidale. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Question on lithium ion batteries.
No memory on Lithium batteries, that was an effect you would see on Nickel-Cadmium batteries and in a more limited sense Nickel-Metal-Hydride. Only issues with Lithium batteries is they like to be kept cool, and the best long term storage charge amount is about 30%, not full. Menno On 23 January 2015 at 16:42, William Bennett wrbennet...@gmail.com wrote: So, having absorbed, from my friends, the dangers of partially recharging a lithium-ion battery due to “memory”, I read the insert that came with the new laptop battery: – “Recharging a partially charged lithium-ion does not cause harm because there is no memory. Short battery life is mainly caused by heat rather than charge/discharge patterns.” Um, who's right? William Bennett, Armidale. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Question on lithium ion batteries.
Menno, Thanks for the information. I will add this: you'd be surprised how many computer experts, professionals included, labouring under this misapprehension. I asked around because I had been told of the existence of “memory”, but felt that the manufacturers should know what they were talking about. William. On Fri, Jan 23, 2015 at 4:42 PM, William Bennett wrbennet...@gmail.com wrote: So, having absorbed, from my friends, the dangers of partially recharging a lithium-ion battery due to “memory”, I read the insert that came with the new laptop battery: – “Recharging a partially charged lithium-ion does not cause harm because there is no memory. Short battery life is mainly caused by heat rather than charge/discharge patterns.” Um, who's right? William Bennett, Armidale. -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
