Behold the "Prius Simulator"
When building a test system, one wants to be able to confirm its operation independently from the DUT, or "Device Under Test." This is especially true in the case of an expensive and mobile DUT such as an automobile. I salvaged 100 good 2V, 2.5AH lead acid cells from defective battery packs in which other cells had gone bad and connected them in series. The terminal voltage of this assembly is about 240V when charging, and drops to around 200V under load.
For use on the cart I attached them side by side for easier handling and stability.