I recently had to replace the Batteries on my 2015 Z9 because one of them went dry. The reason it went dry is because the tie down strap disintegrated and the battery was bouncing around in its tray causing the battery housing to crack. All of my battery tie down straps were disintegrating and I could see that when they built the boat and installed the tie down straps they had placed the strap on the floor then screwed the Battery Tray down on top of it ....so replacing the tie down straps would be an absolute pain....so I came up with a simple solution ...Zip Ties...not electrical Zip Ties, HVAC Zip Ties. Go to a hardware store , Lowe’s , Home Depot..and go to the HVAC Section, there you will find Zip Ties that are used for large Duct work , they are 3/8” wide and have a load rating of 175 lbs. and come in 3 and 4 foot lengths , I removed my original Tie Down Straps , slid the Zip Tie under the Battery Tray zipped it down ...worked perfectly.