Electrical arrangements at Matri Bhaban. You can see the earthing strip on the wall. The square box with handles at the back is the 3 kVA isolation transformer. The 2 kVA true double-conversion online UPS is the small black box on the right. The battery bank is large, with twelve 26AH batteries (72Vx2 banks in parallel) for roughly two hours backup at full load. Our expected load is about half this capacity, ~ 900 W.