[Non-Touchscreen Windows Mobile Other] Menneisyys:
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.