The MultiPlus and Quattro products play a central role in both AC and DC systems. They are both powerful battery chargers and inverters in one box. The amount of available AC sources is the deciding factor when choosing between the Quattro and the MultiPlus. The big difference is that a Quattro can take two AC sources, and switch between them based on intelligent rules. It has a built-in transfer- switch. The MultiPlus can take only one AC source.