Ideal Charge Level

[Xenon14]

After reading this: http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

I'm curious is there a way to keep a laptop from charging above a certain level, say 60%, while still keeping the power & battery plugged in?

 

[avash]

I have a Lenovo Thinkpad X220. Lenovo's power manager allows you to select custom charging thresholds to do exactly what you are asking.

I can set my laptop to charge up to say 88%, then it will not charge the battery until it drops down to say 44% despite repeated plugging in/out. As long as the battery doesn't drop below your lower set threshold, it won't charge the battery and just run off AC power.

(You can change the setting at any time).

This is one of the reasons I love my Lenovo!

 

[Xenon14]

Thanks. Just got the x120e last night, and put this feature to use. (Takes some digging in advanced battery settings, but it works like a charm). Thanks again!

 

[WackyDan]

You're fine to limit the top end charge to 95% or 96%. Your lower charge trigger can be what ever you find works for your use case.

In may of 2008 I set my thresholds at 50% and 98% on a brand new R61 that I used as my core work machine through Dec of 2010, and still have in use today. I was a heavy traveler, but also carried the Lenovo AC/DC adapter with me so even in the car I was powered most of the time.

My battery started with a design capacity of 56.16 WH....

It now has 150 charge cycles on it.

It now has 34.25 WH (edit - Performing a battery reset brought it back up to 41.02 WH)... I would say that it has dropped most significantly these last 6 months due more to age at this point.

So... Bottom line is, you do not need to set you upper threshold to anything stupid low like 80%. Don't hamper yourself. Yes, set charge thresholds and you will benefit from longer battery capacity, but ultimately you can not fight the aging of a lithium ion battery.

* Former Lenovo Field Engineer... 2006 through 2010.

 

[Zap]

ultimately you can not fight the aging of a lithium ion battery.

That's my thought too. I'd settle for just having great battery life as long as that lasts.

 

[WackyDan]

I stand corrected. I just performed a battery reset... and my capacity is back up to 41.02 WH....

So there.

 

[imagoon]

I have personally in my "unscientific tests" that most Lithium cells seem to last longer as long as a) the charger is smart and doesn't over do it (IE use quality batteries) and doesn't try to charge past 100%. b) don't discharge to 0% rather plug it in when able even if the the cells are 85% etc. Sitting all day in a laptop dock @ 100% will age them faster than a mid 50 - 40% shelf charge etc.

 

[WackyDan]

Sitting all day in a laptop dock @ 100% will age them faster than a mid 50 - 40% shelf charge etc.

Not if you have your charge thresholds set right. At a 50% lower threshold my battery could spend a few weeks in my dock before it ever actually charged.

 

[imagoon]

Not if you have your charge thresholds set right. At a 50% lower threshold my battery could spend a few weeks in my dock before it ever actually charged.

Then turn around and explain to your executive staff why they only have 50% battery life when they take the machines home on the weekend. In general in my office the battery replacement period is almost on the same cycle as the laptop replacement cycle. Of of a group of 30 laptops typically only 2-4 batteries are unusable.

I also would personally prefer taking 6 months off my batteries life than only get 3-4 hours of life when I could get 6-8 and not have to run around looking for an outlet.

 

[WackyDan]

Then turn around and explain to your executive staff why they only have 50% battery life when they take the machines home on the weekend. In general in my office the battery replacement period is almost on the same cycle as the laptop replacement cycle. Of of a group of 30 laptops typically only 2-4 batteries are unusable.

I also would personally prefer taking 6 months off my batteries life than only get 3-4 hours of life when I could get 6-8 and not have to run around looking for an outlet.

I never suggested this is something that you set for your users. I had very few customers that did force these settings, otherwise they never touched them.

This is more of an individual's preference versus something that should be set as policy. In the case of one customer who mandated thresholds, we talked them into buy AC/DC adapters to alleviate the concern of over all battery run time when out in the field.