ULTRA Deep Cycle Batteries NZ. Ultra Batteries are manufactured in the USA and offer reliable, proven, deep cycle performance. Plate grids range from 2.2mm to 5mm thickness with glass mat separators and hot melt cell group bonding. This robust construction provides excellent cycle life and a high resistance to corrosion when subjected to top-off and float duty charging voltages. Ultra Batteries are Endurant Batteries labelled as Ultra batteries, for those that know Endurant Batteries, you'll understand the quality. Click on any listed product to buy and/or for more information.