Cove, I would recommend you check the battery in the old one NOW. If it looks dry, that is, the white separators visible between dark plate tops, add just enough distilled water to make the separators look wet and no more. Then check in a month to see what it looks like. Let it go for two months for the next check if they are still wet. Start looking for a new battery if you have to "wet" it every month. I think mine worked for about a year before it acted up. Its life could have been extended had I checked it sooner.
Karl