Prolonging lithium ion battery life

Prolonging lithium ion battery life

Post by pf » Mon, 07 Mar 2011 10:34:00


I have been involved in a long standing debate. One of us believes that
your battery will last longer, particularly if most of your laptop use
can be AC assisted, from being plugged in. The other party says you
should run the battery down and then charge it up. The later was
certainly true when we had NiCd's, but they went out with the dinos.
Does anyone have a link(s) which tests this with a good protocol and
real numbers?

--
During times of universal deceit, telling the truth
becomes a revolutionary act.
George Orwell
 
 
 

Prolonging lithium ion battery life

Post by Wes Grolea » Mon, 07 Mar 2011 11:12:50


This has been asked before, and answered with a link to Apple's page
where they recommend keeping it fully charged most of the time but
once a month letting it run almost all the way out.

Letting it run out occasionally "recalibrates" the components that
tell you how much time you have left.

But each battery model has a predicted life of some many charge cycles.
If you run it all the way out and recharge it every day, you use
365 charge cycles in a year. If it is rated for one thousand, then
you'd have to replace it in three years.

--
Wes Groleau

Holly on Holiday
http://www.yqcomputer.com/

 
 
 

Prolonging lithium ion battery life

Post by Kevin McMu » Mon, 07 Mar 2011 12:33:55

In article <1jxoh4z.utabq113ytyt6N%pf@porkain'tkosher.oink>,



Some LiPo charge levels age faster than others, but there's no way to
know what the charge indicator actually corresponds to in terms of
chemical energy levels. A manufacturer can adjust the minimum and
maximum allowable charge to optimize long term performance. Guessing
what to do will probably waste your time.

Apple recommends a periodic full discharge/charge cycle to keep the
battery power meter calibrated. Without calibration it becomes
non-linear; it may count slowly then speed up. There's nothing more to
it than that.
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Prolonging lithium ion battery life

Post by Alan Brown » Mon, 07 Mar 2011 23:37:55


That's a rough guide. I'd bet in the last 1/3 of the life of the
battery that the endurance per charge would be fairly low.

Generally though with NiMH and Li-ion I don't worry too much about
battery state.

I bought an iPhone 4 last week. If I leave in the morning with a topped
up battery I can just get 2 full days out of it. But as I use it more
and more in the day (with a few useful apps), that is sure to go down to
a nightly charge or more likely I'll be doing "stretch" charges over
lunch on the 2nd day.

A cool thing is how well the iPhone works with MS Exchange at work.

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gmail originated posts filtered due to spam.
 
 
 

Prolonging lithium ion battery life

Post by Alan Brown » Mon, 07 Mar 2011 23:42:55


The only "rule" I know about Li-ion is for prolonged storage. For that
you're best to run down the battery to about 40-60% before storage.

I bought a new phone last week and the battery was at 45% when I turned
it on for the first time which (possibly) validates that storage charge
point.

Wes points out that its good to run it down mostly from time to time in
order that the circuits/firmware that estimate charge can have fresh
calibration points. I haven't seen the page he refers to, and if he's
too lazy to link it, I'm certainly not going to do it for either of you. ;-)


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gmail originated posts filtered due to spam.
 
 
 

Prolonging lithium ion battery life

Post by Suze » Tue, 08 Mar 2011 01:33:43

In article < XXXX@XXXXX.COM >,




http://www.yqcomputer.com/
--
Start every day with a smile and get it over with.
 
 
 

Prolonging lithium ion battery life

Post by Wes Grolea » Tue, 08 Mar 2011 13:40:14


I've seen it, but I am too lazy to go find it when anyone who needs
to read it has been informed it exists, and has more than one way to
find it.

--
Wes Groleau

Liar, Liar, Pants on Fire!
http://www.yqcomputer.com/
 
 
 

Prolonging lithium ion battery life

Post by Lewi » Tue, 08 Mar 2011 16:06:23

In message <1jxoh4z.utabq113ytyt6N%pf@porkain'tkosher.oink>


The Lithium ion batteries have a certain number of recharge cycles. The
more you use the battery, the more cycles you use. If the machine is
stationary, leave it plugged in.


--
The voice of the majority is no proof of justice.
 
 
 

Prolonging lithium ion battery life

Post by Kevin McMu » Wed, 09 Mar 2011 05:44:20

In article < XXXX@XXXXX.COM >,




That's not entirely correct. LiPo/LiIon ages whether it's cycled or
not, and the speed of aging varies by factors that are hard to control
unless you're the manufacturer. In normal use, calendar aging may be
more rapid than usage aging.
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Prolonging lithium ion battery life

Post by John McWil » Wed, 09 Mar 2011 10:45:19


Although it does seem irrefutable that the more you use the battery the
more cycles you use, but how that affects aging is apparently an open
question.
I don't know how you'd compare the two types of "aging".
 
 
 

Prolonging lithium ion battery life

Post by Wes Grolea » Wed, 09 Mar 2011 13:47:48


And the manufacturer of Mac laptops says both, i.e., keep it charged
as much as possible except occasionally run a full cycle.

--
Wes Groleau

Guidelines for judging others:
1. Don't attribute to malice that which
can be adequately explained by stupidity.
2. Don't attribute to stupidity that which
can be adequately explained by ignorance.
3. Don't attribute to ignorance that which
can be adequately explained by misunderstanding.
 
 
 

Prolonging lithium ion battery life

Post by pf » Fri, 11 Mar 2011 02:58:00


Unless you can accelerate your laptop to near light speed when not in
use, there is not much you can do about aging. Sort of a linear
function - time that is, if not deterioration. My personal physical
deterioration is asymptotic to the y axis.

As the OP, no one seems to see any links to hard data test(s) with
numbers and parameters. We just have to take the manufacturers' word on
it. Remember (1920's - maybe not) when Lucky Strike cigarettes were
advertized as health promoting? But corporations wouldn't lie about
their products today :-)
--
During times of universal deceit, telling the truth
becomes a revolutionary act.
George Orwell
 
 
 

Prolonging lithium ion battery life

Post by J Burn » Fri, 11 Mar 2011 06:04:48


Cadex Electronics has tested lithium-ion batteries.

At freezing with 40% charge, they lose 2% capacity per year.

At 25C with 40% charge, they lose 4% capacity per year, but 20% if left
with a full charge.

Left fully charged at 40C, they lose 35% capacity per year. At 60C it
takes only 3 months to lose 40% capacity.

For recharge cycles, they have gotten

500 at 100% discharge
1500 50%
2500 25%
4700 10%

So recharging at 10% instead of 100% costs only 6% in battery life,
while recharging at 50% gets you 50% more battery life.
 
 
 

Prolonging lithium ion battery life

Post by David Ros » Fri, 11 Mar 2011 10:21:50

In article < XXXX@XXXXX.COM >,




But doesn't Apple suggest otherwise?

David - who has more faith in Apple than Lewis
 
 
 

Prolonging lithium ion battery life

Post by Wes Grolea » Fri, 11 Mar 2011 11:13:46


No. Check out the URI someone offered earlier in this thread
for Apple's advice on battery life.

--
Wes Groleau

Local Cheerleaders Make Newsweek
http://www.yqcomputer.com/