If you have electric brakes, a battery is REQUIRED. The battery supplies the power to the brakes if the trailer breaks away from the towing vehicle.
Batteries give off corrosive and explosive gasses so they are usually in a dedicated battery box. A battery box is not required but it is any easy way to secure a battery on the tongue, keep the gasses ventilated, and keep other things from becoming corroded.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.