On Pedro Clisante (the street where all the bars are - Britannia, La Roca, Playero supermarket (the little one), etc. there is a camera store and I'm sure you could go and ask if they have a charger and pay them a fee to charge your battery without having to buy the actual charger. My husband and I get pictures developed there all the time on holidays and the owner if very fair with his prices and has accomodated several different odd requests we have had in the past. At the very least, he will be able to refer you to someone who can help. The store is on the opposite side of the street from the Britannia Pub and between there and the Playero store. Hope that helps.
