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What Are the Requirements for an Electric Vehicle Charger to Be Vehicle to Grid Capable?

(Joseph Gottlieb, CTO, Tuesday, July 7, 2020)

As our previous blogs pointed out, vehicle to grid (V2G) is a complex undertaking that has the potential to provide a lot of value to EV fleet operators that implement it. Clearly, the first thing that is required for V2G (beside a fleet of electric vehicles) is a bi-directional AC-to-DC charger which has been certified to the relevant specifications. For V2G, there are two specific requirements that equipment must meet to operate in the US: UL 1741SA (“Standard for Inverters, Converters, Controllers and Interconnection System Equipment for Use with Distributed Energy Resources”) and UL 9741 (“Standard for Bidirectional Electric Vehicle Charging System Equipment”).

Meeting these specifications is not the end of the process – these are the ones that are specifically for V2G operation. AC-to-DC 4EV charging infrastructure components still have to meet a variety of other safety specifications, such as:

  • ANSI/UL 2202 (Electrical Vehicle Charging System Equipment – AC to DC)
  • ANSI/UL 2231 (Personal Protection Systems for Electric Vehicle Supply Circuits)
  • ANSI/UL 2251 (Electric Vehicle Plugs, Receptacles and Couplers)

Finally, there are the electromagnetic compatibility (EMC) and electromagnetic interference (EMI) requirements imposed by the Federal Communications Commission (FCC) on all electrical/electronic equipment. Our next two blogs will look specifically into the requirements of UL 1741SA and UL 9741.

Rhombus chargers are designed from the start for the needs of fleet operators. As a leader in the development and manufacturing of bi-directional, high-power energy systems for both vehicle charging and photovoltaic solar applications, Rhombus is an expert in high-power charging systems for EVs, and especially in the area of V2G charging. Rhombus is also an expert in the design and testing of high-power electrical equipment to meet the requirements of UL and other certification organizations. We have built hundreds of V2G-capable high-power, high-reliability chargers for a variety of different sizes and classes of EVs. Find out how we can help you by contacting us at, or by reading our Energy Storage Reference Architecture white paper.

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