This particular charger has a loose fitting 12 volt battery inside, which is only supported on it sides by cardboard. So, YES, it appears to have something loose inside; however, use a flat blade screwdriver and pop the top off and you will see what I mean. I took out the cardboard and inserted foam, but fiberglass insulation will work and so will small PVC.Now, as for operation, I only have a third of an acre in which I mounted two 12.5 gauge aluminum charger wire strands near the top ( but below the top rail ) on the inside of a six foot commercial quality chain link fence. Okay, so maybe it is overkill (no pun intended), and while the analog meter on the face of the charger is pegged over the 10,000 volt mark. WOW . . . but not to worry that is not a bad thing. The chain link fence acts as ground and has much better conductance than a dozen ground rods.
Rating: [5 of 5 Stars!]