e encontrado a un tio que le pasaba lo mismo y lo soluciono o eso dice aqui os lo dejo:
How I solved my battery not charging problem
Hi, yesterday I had a problem charging a new psp battery, I've read some people have been experiencing the same so maybe it can help, I've let it charging for hours then I powered the psp on and the battery was still not charged and the battery info was saying 0% charge complete, I let the power adaptor plugged, powered the psp on (it didn't power on with the battery) and removed/connected the battery (just moved it a little till there's no contact then replug etc...) something like 3 times till it began charging again (it didn't charge before as it was considered full) and ... it works now, I've let the psp running all the night to empty the battery and I'm recharging again and no problem