There’s an exception to every rule. So runs the popular saying and it applies particularly to motorsport. As Formula E moves into its new era of competing manufacturers, looking for loopholes in the technical regulations has become part of the game.

The FIA may have found one such instance of nefarious ingenuity in Formula E’s second generation powertrains already: using the inverter as an undetectable energy reservoir to beat energy and power caps.

The inverter is a hardware unit that is used to transfer energy from the race battery to the motor. Similar devices are known as speed controllers, rectifiers or power electronics. A key part of the inverter’s function is to convert between the DC electrical feed sent from the battery to the AC feed that the motor requires. Because the electric motor is also a generator, this is a two-way process.

To function properly, the inverter stores energy briefly in capacitors. Normally, the size of these capacitors would be just large enough to suit the conversion process. However, enlarging these components could allow for additional energy storage within a Formula E powertrain, outside the race battery.

Why is this a significant suggestion? The regulations govern how much energy a driver may use during a race stint, peak power in race mode or qualifying mode, and how much energy may be returned to the battery under regenerative braking. Critically, the FIA sensors used to police those figures are found around the battery.

In the first season, the inverter was a spec item, supplied by McLaren Applied Technologies. Teams could not meddle with it. Under season two regulations, the inverter is available to manufacturer teams to redesign or replace. If a constructor enlarged the capacitors inside their season two inverter, effectively creating super capacitors, that could allow drivers to capture additional energy under braking and discharge it under acceleration, all without involving the race battery and therefore escaping the attention of the FIA data loggers.

Supercaps are used for high power density and are relatively small. They also cycle their energy rapidly, so are ideally suited for capturing energy from a short braking stint and then discharging quickly to boost a subsequent burst of acceleration. Think KERS.

The advantages of such a supercap inverter system would be numerous. It could allow a driver to invisibly exceed the peak power limit in qualifying and the race for brief periods. That would make pole position easier to grasp and create a performance gap large enough to drive away from any competitors in the race itself.

The system’s store could allow more energy than permitted to be harvested from regenerative braking. This would add to the usable energy limit in the race, without discovery, allowing the driver to go further or faster than competitors. It would also reduce stress on the battery itself, which is prone to thermal issues during the race.

While we can’t confirm that any Formula E team has built such a system, speculation is rife within the paddock that supercap inverters are in use. “When the FIA homologated season two powertrains, they looked at basic components,” one source told us. “There were some open areas in the regulations. A few teams worked out that this could allow them to store energy outside the RESS [the main race battery system]. A lot of energy can be stored in the inverter and we’re capable of regening a lot more energy than we’re allowed to. It’s not an easy technological challenge and it would add some weight, but the performance gains if you made it work would be extraordinary. Many constructors looked at systems like that but it would become a crazy arms race.”

There’s no suggestion that the use of supercap inverters is technically illegal under the current regulations. Inverters already have capacitors and there’s no definition set on their use or period for which they can store energy. Using such a system would underline the careful thought and innovation that has gone into Formula E’s second gen powertrains.

However, the FIA would take a very dim few of a team circumnavigating the power and energy caps, regardless of how it was done, and would look for ways to close the loophole for the following season.

Scarbs is technical editor at Current E. Follow him: @ScarbsF1