How do you tell if the battery is on and actually working, for instance, after several months of use how will I tell if is still working and that I don't need to replace it?Updated a year ago

The Ocean Guardian FREEDOM+ has LEDs which give an indication of several checks; 1) a self-check on start-up to ensure the electronics and electrodes are functional, 2) whether the decal electrode is in water or not, and 3) the battery level. You will visually see that the battery and output is healthy, and before the battery begins to go flat you will be given a visual alarm as well as an audible sound to let you know you have approximately 20 mins left before the Ocean Guardian is no longer functional.