Charge your battery as often as possible - revolutionary, comparative, numeric results!
I’ve, in all Windows Mobile forums, very often posted on the fact that Lithium-Ion / Polymer batteries should always be recharged whenever possible. That is, you should put your handheld / handset on the charger whenever possible. NEVER EVER wait before the handheld shuts down because even after only 4 months, your battery will only hold about a third (!) of its original charge holding capacity and, as opposed to what several people say, putting the device on the charger only once a day (or two-three days with devices with better battery life – mostly, TI OMAP-based handsets) on a regular basis (not waiting for the battery to completely deplete) will also have an adverse effect on the battery life.
Now, Groucho's pretty cool Nokia N95 blog has published a remarkable article, which is of extreme interest to anyone having a device with a Lithium Ion or Polymer-based rechargeable battery (not only Nokia N95 users – again, this info applies to ALL current Windows Mobile handsets, and a lot more other gadgets like digital cameras etc.). The figures he shows certainly prove I’ve been right when I recommended recharging your device whenever possible.
Groucho has purchased three N95’s (again and again, don’t think this discussion only applies to the N95 – it does apply to ANY device out there!) at the same time and used them in a pretty similar way. He, however, made absolutely sure he charged the device in three consistent (not mixing up the devices) and radically different ways: the first was charged only once a day (every night), not during the day; the second was charged when it has completely shut down because of the battery’s going flat and the third was almost always on charger whenever possible. The difference in the battery capacity, based on the different ways of recharging, turned out to be astonishing: the second battery (which was always let go flat, and only after that was it put on a charger) could only hold slightly more than a third of the battery that was always on charger whenever possible. The latter battery, in addition, fared considerably (about 16%) better than the battery only regularly (every night) recharged.
Note that the blog post has a mistake (which has no effect on the credibility of the results): it states they will have exactly the same charge holding capabilities throughout their life, and, suddenly, they die (“They have a finite shelf life which starts from the day they are manufactured and their condition from then degrades to the point where they fail! This is not to be confused with their charge holding abilities which are very good for their full life! When they go they just go!"). This is, of course, incorrect: their capacity will degrade over time. Just an example: my HP iPAQ 2210, which I bought right after it was released in Europe, at first, shut down at 2-3% battery level. After about two years, this raised to about 20% and, after three years, this was already around 35-38%. This also shows – along with a multitude of other examples – that these batteries do lose capacity over time. Also note that, as I’ve also recommended several times, Battery University has a decent article on all these questions – except for, of course, real-world results like the above.
Verdict: ignore if somebody says the opposite. Recharge your handheld whenever possible.
Cross-posted to (might be worth checking out for additional info / discussions!): MoDaCo, HowardForums, FirstLoox, PPCT, AximSite, XDA-Developers - 1, XDA-Developers - 2, BrightHand, SPT.
UPDATE (11/07/2007): YAMM frontpage with additional comments.
- Login or Register to post comments
Printer-friendly version
Thanks for this. I try to start each day with an (almost) fully charged device, so if it's not completely charged by my laptop (Active Sync) when I go to sleep, I put it on the charger at night. It's also quite often connected to my laptop when it's at 100%, so I'm glad I don't have to worry about this.
Somehow I never thought about this; however, I came across some similar info today, in a completely unrelated type of story. My wife and I are currently sharing one charger (she lost hers) so I'm regularly getting the battery down to about 30% - she just loves going to complete failure! I'll go out and get another charger - Thanks!
Hi Werner,
I posted a link to your article in a local PDA forum, and was referred to the following link, that I understand reached different conclusions:
http://www.dell.com/downloads/global/vectors/2005_batterylife.pdf
Daniel, thanks for the link!
The PDF you’ve linked indeed discusses how battery life can be improved (which can indeed be done on a notebook computer by decreasing the backlight level, disabling unusaed hardware, decreasing the CPU clock frequency etc), but only during one session (to provide the best battery life with one charge), not through the entire life span of the battery (that is, to help the battery keep its capacity after months of (heavy) use and recharges).
The article I’ve linked focusses on the latter issue: instead of telling the user to decrease the backlight level, disable Wi-Fi etc., it compares the three most important, widely used - and, last but not least, with real-world statistics and figures, in the past, not really backed up - approaches of recharging batteries. Should the Dell document have gone the same way, they would have stated for example “only plug-in your notebook when its battery is just about getting flat or, alternatively, remove the battery if you don’t want to do this unless you can live with the disadvantages of running on battery” vs. “make sure you always keep it on a charger”. Or, alternatively, they would have explained “we constantly monitor the charge level of the battery and when it decreases under a certain threshold (which is, BTW, around 95% on Thinkpad notebooks), we start recharing the battery”.
Hi Werner,
So basically, you hold your position?
Sure I do - the Dell PDF is on an entirely different matter. It speaks of short-term (between two recharges) battery life and the ways of extending it, while I elaborate on long-term (months / years) battery capacity degradation and the ways of avoiding it.
These two approaches have nothing in common - the two articles have a completely different subject.
Hi all,
Many thanks for the link, Werner.
I hope that the results are of use to anyone using Li-ion (and polymer)cells!
Just to clear up the 'lifespan' espect that you raise.
My comments in this respect were probably over simplistic and I accept your observation.
My point was to try and diferentiate between the lifespan and the on going operating capacity which are indeed seperate issues.
I was trying to convey that Li-ion cells can hold their operating capacity over their lifespan better than other legacy battery technology.
Date of manufacture is important as Li-ion chemistry starts to degrade as soon as it is manufactured.
One result of this is that two batteries purchased at the same time will 'fail' at approximately the same time which suggests that staggered purchase will give a longer operating lifespan from the same two batteries.
I have a crude test on these lines going at the moment, but, it will be some time before I have any results. I'll post when I have them.
Regards.
Groucho, thanks for the comment; looking forward for your new results!
If you need a new laptop battery, I suggest you could purchase one from http://www.batteryfast.com , which would shipping to you fast and the quality is satisfy satisfied.:)
There Are Several Steps You Can Take To Help You Get Maximum Performance From Your Power Tool Battery: Prevent Memory Effect - Keep The Power Tool Battery Healthy By Fully Charging And Then Fully Discharging It At Least Once Every Two To Three Weeks. Exceptions To The Rule Are Li-Ion Batteries Which Do Not Suffer From The Memory Effect. Keep The Power Tool Batteries Clean - It's A Good Idea To Clean Dirty Battery Contacts With A Cotton Swab And Alcohol. This Helps Maintain A Good Connection Between The Battery And The Portable Device.
A recent survey indicated that, given the option of larger size and more weight for longer runtimes, most users would settle for what is being offered today.
Batteries For Laptops Have A Unique Challenge - They Must Be Small And Lightweight. In Fact, The Laptop Battery Should Be Invisible To The User And Deliver Enough Power To Endure A Five-Hour Flight From Toronto To Vancouver. In Reality,
You can be assured that the information you give us is confidential. We do not sell, rent or share information of our customers with other parties.
sir,it is like as you have said that
http://www.e-lw.com
http://www.laptopbatterybbs.com
http://www.lw-blog.com