Safety is a huge concern for electric vehicles, and the problem with permanently-connected batteries is that a high voltage is always available somewhere. The frame of the vehicle gives a path for conduction, and if a battery is punctured against it in an accident, this not only represents a fire hazard but a shock hazard as well. The Green Roof Solar, LLC multilevel inverter does not suffer from this problem. The highest voltage available in an accident, or whenever the vehicle is not moving, is a mere six to twelve volts. This is not enough to cause a shock hazard, and even during a short, the problem is confined to one battery as current cannot flow to those around it.
Our multilevel inverter design has only thin printed circuit boards mounted on each battery, which typically would be necessary in a non-multilevel design, and two contactors, seven relays, and a master circuit board inside a small control box under the hood. This opens up the hood for use as a storage area or allows room for more batteries. Additionally, batteries can be added or subtracted from the system and are automatically accounted for by the control box upon vehicle re-initialization. A trailer with fully charged batteries can be put in series with the vehicle’s original battery pack, and even if the on-board pack is nearly dead, the vehicle can be operated normally as long as the trailer holds charge. The trailer can also recharge the on-board pack while driving in a completely regulated manner.