Output time won't scale with salinity that way. Conductivity will vary more-or-less linearly with salinity, and output power will vary more-or-less linearly wit

Output time won't scale with salinity that way. Conductivity will vary more-or-less linearly with salinity, and output power will vary more-or-less linearly with conductivity, so with lower salinity you'll get less light (lots less light) but the battery will last for a concomitantly longer time. Batteries run on the anode/cathode pair--not the electrolyte, as this page dishonestly suggests--and as such the total energy available will be determined by those, not the electrolyte. If you wanted to use urine in this device you'd be best to concentrate it by evaporation to get a reasonable output brightness.