But don’t leave it fully charged either
Strangely, our phone batteries don’t like to sit idle when they’re charged to 100 per cent, either. In fact, the experts at Battery University say a Li-ion’s “sweet spot” is a charge of somewhere between 30 and 80 per cent.
So, unplug the charger before the battery is fully charged, and definitely don’t leave it charging all day or night, since that will leave it at 100 per cent for too long. Of course, you won’t kill the battery by doing this from time to time, but we’re talking about the ideal way to get the longest life from it.
Keeping the battery in the “sweet spot” might mean plugging it in a couple of times a day, especially if you use the device compulsively. But when you do charge it up, Blackberry says to make sure it’s a long charge, since they recommend against “small increment” boosts of 15 minutes or less.

Keep it cool
Cellphones perform best at room temperature. As any Canadian who has used a phone in the winter knows, the battery drains quickly in the cold.
But what’s even worse for the battery is heat. Never leave a phone (or any electronic device) where temperatures could go higher than 35° Celsius, such as in a hot car. Doing so can permanently damage the battery, making it less able to hold onto a charge afterward.

HP 650 Battery http://www.dearbattery.co.uk/hp-650-battery.html
Lenovo Thinkpad L510 Battery http://www.dearbattery.co.uk/lenovo-thinkpad-l510-battery.html