1.
Plug in the power adapter and fully charge your PowerBook's battery until the light ring or LED on the power adapter plug changes to green and the onscreen meter in the menu bar indicates that the battery is fully charged.
In other words, charge the battery until it's full.2.
Allow the battery to rest in the fully charged state for at least two hours. You may use your computer during this time as long as the adapter is plugged in.
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Thank you very much 😀 Just one thing: you said in point 1 that I have to let it fully charges, and in point 2 to let it still charges for a couple of hours (while I can use it, if I want)... This make me wonder (I'm sorry if look stupid but I really care about this): can also use it while charging to 100% (so as soon as I turn it on) or only when it's already fully charged and I'm letting it plugged in for "those couple hours" you said?
Long story short, as soon as I get home I had to fully charge it without using it, charging it while using it or using it for a while and then charge it?