[HarryT]

Originally Posted by BlackVoid

One of your problem was definitely the memory stick.
Read this how to preserve battery capacity for Lithium-ion batteries.
http://en.wikipedia.org/wiki/Lithium-ion_battery

DO NOT DISCHARGE OFTEN! This is one of the golden rules.

There seems to be considerable disagreement amongst the "experts" as to whether or not this actually is a "golden rule". Many sites inform one that frequent "top-ups" do no harm at all to a LiIon battery, while others say it should be avoided.

No matter what you do, though, the fact is that your battery is going to lose capacity with time; the best you can hope to do is to slow the process down.