PSP battery : how to charge it correctly ?

[Plod]

Hi,

I work as a service tech at an Apple centre and get the battery question quite a lot. Powerbooks, iBooks and iPods all use Li-Ion, as does the PSP and this is the advice that I give to my clients:

Li-Ion batteries don't have a memory effect and it doesn't matter when you recharge them, but they will slowly lose the ability to hold a charge. Typically, with things like the iPod and PSP, about 400 recharge cycles is the expected lifespan of the battery. What's a recharge cycle? One full charge from empty to full. But how does it work if I don't flatten my battery? If you use your battery to 50% and then charge it that's 1/2 a cycle. next time you may use 20% then charge.. so, when you have used 100% (over one or several charges) that would be one cycle.

You may hear that to fully dischage a Li-Ion battery is bad. Sure, it can be but there are some exceptions to the rule. Most Li-Ion batteries will 'go flat' while some residual chage is still left in the cells. There is battery monitoring electronics built into the battery to do this, so it's ok - as long as you charge the battery up asap. If you fail to charge a fully drained battery up, there is a risk that the residual charge will be lost - dropping the battery into a 'deep sleep' that can be virtually impossible to revive. So, why would you want to run the risk of a dead battery then? Have you noticed that Laptops, iPods and PSP's all have a thing to tell you how much time is left in the battery? Have you ever noticed that sometimes it will say that it's at 0% but the device keeps working, or it might be at 100% and keeps charging? That's because the battery requires a re-calibration of the monitoring circut. To do this, you need to run your battery to 'flat' and then give it a full, continuous charge.

I try and do my iPod once a month or so, but as I am inherantly lazy and don't remember to charge it always, I find that every other week it goes flat. My powerbook is a little different, I have to 'remember' to not charge it. So I find a time when I can do some work at night in front of the telly and work off the battery until it dies - then I stick it on to charge and leave it overnight. Again, once a month is a good thing to keep the battery calibrated. But be prepared to put it on charge as soon as possible.

So, what kills a battery if I keep it charged up and look after it?

The biggest killer of batteries beyond simple use and neglect (of charge) is heat.

Who uses a laptop? Have you noticed how hot your laptop gets? It's slowly cooking your battery. Simple as that. The cooler your battery, the longer it will last.

Do you have a spare battery that you don't use? Give it a 50% charge and leave it somewhere cool - even your fridge is ok as long as there is no risk that it will feeze (as this, too, will kill your battery) and no risk that it will get wet (stick it in a zip-lock bag and make sure that it returns to room temprature before you use it)

How long will a Li-Ion battery last? A couple of years at best - even if you don't use 'em. So if you have a spare battery that you are going to save for when your current one dies, use it now. Alternate it with the battery you have as the clock starts ticking on the battery life from the moment it leaves the factory.

Hope this helps.

Plod.

[PSP_Newbie]

wow, nice explanation, you really know what you're talking about
guess you really do learn something every day, thnx