Just wana share wit my fellow "P1ians"
It might seem like a trivial subject, but keeping your P1i battery in tip-top condition is quite important for those who need the extra juice to survive for the half-day outing. Or simply put, you just want to maximise the life span of the battery you currently own. In any case, this is one guide worth reading.
1. Memory Effect
You might have heard before that you should fully drain the battery before recharging it, as this would allow one to completely fill up the battery to its capacity as opposed to charging it when there is still 50% left in the battery. This is good advice for Nickel based batteries, which suffers from the so called "memory effect". However, since Lithium batteries do not suffer from this problem, there is no reason to fully discharge the battery before recharging.
In any case, it could even be harmful for your Lithium battery, as constantly discharging your Lithium battery may leave it short of its capacity or even render it unusable if you do it enough times.
2. Calibration
Okay, fine. In order to get accurate battery readings from your phone, you might want to discharge your phone once in a while, i.e. once every two months. This allows the system to get the readings accurate again. Don't you ever have that situation where you wonder why the battery meter keeps jumping around?
3. Temperature
Heat is the enemy of Lithium batteries - try not to overcharge your batteries. What I mean here is to get it off the charger after it says "Full Charge" or when its "99%".
4. Proper Storage
Let's say you're going on a hiking trip and you can't bring your P1i along. Or something of that sort. If you don't use the smart phone for a prolonged period of time, try keeping the charge in the battery at about 50%. Why? Because if you keep it at full charge, the battery has unnecessary stress and may cause internal corrosion. On the other hand, if you keep it at too low a charge, it may render it completely unusable because of the battery self discharge. Yes. This means you should keep eating away at the battery until is 50% - play games, put the music to maximum, show a slideshow. That will bring the battery down.