I have two Renogy 170 ah batteries in parallel on my boat. They are about three years old and according to my Rover charge controller they have been fully charged 116 times. I would like to purchase a third Renogy 170ah and add it to the existing 2 batteries in parallel. Any advice? What will be the pitfalls of doing this? advice? What will be the pitfalls of doing this? Note these are not the newer Renogy smart batteries.