The wash basin has a leak. I think we have to change the battery.
This does sound rather dangerous as, let's face it, water and electricity don't mix. So I’ll correct first: It should be ‘I think we have to change the tap’.
I must admit I was confused by this one. As far as the dictionaries were concerned, the literal translation of ‘battery’ in the Polish language is battery. Eventually, it took a technical dictionary to work this one out.
When you go shopping in a hardware store in Poland to buy yourself a new mixer tap – a tap from which both hot and cold water can come out – many display them as bateria łazienkowa. However, when talked about informally, łazienkowa is dropped, leaving us with just bateria which, in context, makes sense in Polish. But in English – well…
I think the problem is that ‘bateria’ also means ‘bank’ in the meaning of ‘a store of something’, and as a mixer tap supplies both hot and cold water, I assume this where the word comes from.
On a cultural note (number 1), any non-Brits like to have a quiet giggle when they see British sinks with two separate taps for hot and cold water perhaps need to know there were some hygienic reasons for this - note the past tense were as opposed to are.
Up until very recently, most British homes used to have hot and cold water from two separate sources: cold would be fresh, but hot would come from a separate water tank, usually stored in the roof and therefore get easily contaminated. These days most homes now have fresh hot and cold water, but we Brits have become used to the separate taps.
Thankfully many Brits are getting used to the idea of mixer taps installed – and then they wonder why we’ve had separate taps for so long. But there are still many who quite like the separate sources of hot and cold water.
On another cultural note (number 2), a tap in American English is a faucet.