As electric vehicle (EV) manufacturers look to decrease the charging times for their vehicles and to increase overall energy efficiency, higher system voltages become necessary for the continued evolution of those vehicles. Magnetic components and the windings used in those components also need to be able to handle the higher operating voltages, as a result. Some of the benefits of these 800+ volt batteries and systems cited by manufacturers are:

  • The battery in the new 800 volt Hyundai Ioniq 5 can be charged from 10 to 80 percent charge in just 18 minutes when connected to a 350kW DC fast charger. 1
  • Voltage and current are inversely proportional, meaning that an increase in voltage results in a decrease in current for the same amount of power being transferred. Where less current is required, smaller conductors can be used, resulting in a reduction in overall weight and longer range for the electric vehicle. 2
  • Battery charging becomes more efficient, due to lower electrical currents and less heat generation in the charging process. 2

To meet the evolving needs of the EV manufacturers, Rubadue Wire has expanded the company’s certifications with VDE to include 1,000 Vrms ratings to IEC 61558 on the company’s triple-insulated ETFE and PFA wires. Transformer manufacturers looking to serve the EV market and EV manufacturers can now look to Rubadue Wire as a manufacturer of the winding wires used in transformers for 800, 900, and even 1,000 volt onboard systems and charging stations.

So, what does this mean in terms of the power electronics on an EV? First, let’s look at a simplified diagram of the electrical parts on board of a typical EV.

Fig 1: Simplified EV Electrical System Diagram 3

Image Source: “Electric Vehicle Charging Technology Review and Optimal Size Estimation” by Brenna et al is licensed under CC BY 4.0

The EV’s electrical system consists of high voltage circuits and low voltage circuits. First, you have the high voltage circuits, connecting the high voltage battery to the electric motor, the on-board charger, the DC fast charging plug, and the DC/DC converter. The high voltage circuits provide power to the electric motor, return power from regenerative braking to the high voltage battery, connect the battery to external power sources, and provide power to the DC/DC converter, which steps the voltage down to a lower voltage for the low voltage circuits. On the other side of the DC/DC converter, you have the low voltage circuits connected to the “Electronic Loads”, which include the vehicle’s headlights, taillights, stereo system, power windows, windshield wipers, etc.

Insulated winding wires used in the power electronics components connected to the high voltage circuits need to be rated for the operating voltage used with those high voltage circuits. Most insulated winding wires with third-party certification will have a certification to IEC 60950-1 or UL 60950-1. Those standards, however, only cover equipment with rated voltages up to 600 Vac. With system voltages of 800 and 900 volts being used in newer EV’s, certification to a different standard becomes necessary for transformers and the windings in them, which is where IEC 61558 comes in. IEC 61558 covers the safety requirements for transformers with voltage ratings up to 1,000 Vac. Rubadue Wire’s new 1000 Vrms certification to IEC 61558 means that our triple-insulated ETFE and PFA wires have the necessary certification for use in the transformers and other magnetic components connected to the high voltage circuits in these newer EV’s.

For some perspective on where the broader EV market is heading with system voltages, consider the following:

  • Porsche sold over 20,000 luxury Taycan EV’s utilizing an 800 volts (nominal) battery in 2020. 4
  • Lucid Motors is planning on a system voltage of about 920 volts. 5
  • Rivian and General Motors have planned for a switch to 800 volt systems along the way. 5
  • Hyundai is launching the 800 volt Ioniq 5 with US deliveries starting this fall. 1

Are you designing transformers or other magnetic components for the EV/hybrid/automotive market? Contact Rubadue Sales with any questions or to discuss your wire needs & application and how we can help with our products today!

Phone: 1 (970)-351-6100



ETFE insulated wires – VDE Certificate No. 136743

PFA insulated wires – VDE Certificate No. 6716





  1. Gitlin, J. M. (2021, February 23). Here’s the first of Hyundai’s new 800-volt EVs—the Ioniq 5. Ars Technica.
  2. E&T editorial staff. (2021, February 19). 800V systems in EVs enable longer ranges, faster charging. Engineering and Technology.
  3. Brenna, M., Foiadelli, F., Leone, C. et al. Electric Vehicles Charging Technology Review and Optimal Size Estimation. J. Electr. Eng. Technol. 15, 2539–2552 (2020).
  4. Jenkins, J. (2021, February 24). High-voltage EV battery packs: benefits and challenges. More voltage, more better?. Charged Electric Vehicles Magazine.
  5. Edelstein, S. (2020, September 15). Supplier confirms broad shift to 800V systems for luxury EVs by 2025. Green Car Reports.