YOU SAID:

The battery went bananas.

INTO JAPANESE

バッテリーはバナナになりました。

BACK INTO ENGLISH

The battery has become a banana.

INTO JAPANESE

バッテリーはバナナになっています。

BACK INTO ENGLISH

The battery is a banana.

INTO JAPANESE

バッテリーはバナナです。

BACK INTO ENGLISH

The battery is a banana.