If you are using water from the sea how do you collect and do you need a lot at once?

Question: If you are using water from the sea how do you collect and do you need a lot at once?
- Keywords:
  collect,
  sea water
Asked by Anon to Charlie on 26 Jan 2017.
- Charles Footer answered on 26 Jan 2017:
  
  To collect Sodium ions which are what we can use in batteries from the sea you don’t actually need too much salt water, a couple of litres is enough for most pouch cells. You can see how much salt there is in sea water if you collect a small glass and let it evaporate and see what salt you’re left with at the end.
  
  Another possibility would be to use pure sea water as an electrolyte (the liquid part of a battery) and house the batteries in the sea which is something a few people are looking into.

Question: If you are using water from the sea how do you collect and do you need a lot at once?