What is the difference between pilha and batería?
In the past, bateria was designed to be rechargeable, different to pilha. But nowadays pilhas are also reachargeable (some of them), but every bateria is rechargeable. Search on GoogleImages to see the difference in the shape! :)
Funny! In Germany, "Batterien" are usually the ones you can't recharge (except the one in the car, it's called "Batterie", too) and "Akkus" are the rechargeables :D
"Pilhas" are those small ones you use, for example, in your remote control or toys.
"Baterias" are those bigger ones you use in your car, cell phones, notebooks or any other electronic device.
Why is "Eu preciso de pilha" also correct on the multiple choice? The phrase "I need batteries" is plural and pilha is singular.
when one says "eu preciso de pilha", the other may answer: "quantas?" (although it is singular, as it is in general context, it may mean plural).