PSP 2000 Battery life leak

My PSP 2000 TA-85 with 4.01m33-2 has a problem.

When I fully turn off my PSP (Hold the power button for more than 3 seconds) and leave it there without playing it, for example overnight, and the battery life I checked was 47%.
The next morning, when I turn on PSP and check the battery life, it shows 41% already :confused1: Where is the 6% gone? This problem has been bugging me lots already since my battery life keep leak out without playing it :crying:
I have checked using Keycleaner 1.4 and no faulty key was found.
Does anyone has same problem and give some help? Thanks > <

PS: PSP bought since last year August.

Batteries lose capacity over time. What you are seeing is normal. especially on a year old battery.

I suggest you not run your battery down to zero. Newer rechargables dont like being drained 100 %. If you recharge them about 10 to 20 % you will get longer life from the batt.

I will add battery capacity meters are not as accurate as we would like. You probably have nothing to worry about. and have been lucky to have your batt last so long.

nice pic is that you?

But I thought even not using the PSP and turn off fully won't even drain the battery life so much?
I do recharge my battery whenever reach 20%.
Sometime my PSP will drain till <20% even I charged it 100% and never use it for 1 week. (why? Because doing assignment + many test) XD

XsavioR: The pic wasn't me daughter

The more you use a battery the less charge it actually accepts. For instance think of a rubberband if you stretch it out repeatedly it wears out. Its very close. Battery meters are using some sort of amp or volt reading, and comparing it to a known value or doing maths of general consumption vs observed charge. There are allot of ways to do it. The bottom line is your battery is starting to get a bit old. A year of moderate use (some where around 1000 charge/discharge cycles) is about the life expectancy of a common battery.

Older batteries like Ni-Cad were even more problematic. If you stored them charged it would ruin the capacity. Also if you didnt fully discharge them to zero b4 recharging they retained a memory of the abuse they recieved and could be ruined in one charge.

Newer batteries also have their idiosyncrosies Like Li-Lon or Li-on (i forget to be honest , just woke up) need to be stored with atleast half charge, Shouldnt be discharged all the way EVER, But as a general rule dont retain memory of abuse (as much)

Bottom line if you got a year out of it your doing quite well. Rechargables dont last for ever

Best bet is research the characteristics of the battery you use (google.com) and treat it right to get the kind of life expectancy they are capable of. Losing charge over time is generally a sign you could use a new battery. (when its dramatic loss)