Mazda I-ELOOP Overview

Beginning model year 2014, Mazda has introduced a regenerative engine braking system called i-ELOOP, short for "Intelligent Energy Loop." In this system, a capacitor is used to store electrical energy generated during deceleration. In a conventional system when the vehicle slows or stops, energy is wasted. The i-ELOOP system uses a unique variable voltage alternator that can produce up to 25 volts during deceleration. The electricity that is generated during deceleration is not sent directly to the vehicle's battery, because the battery cannot store more than 12 volts. Instead, the capacitor stores the electricity, up to the 25 volts produced by the alternator. The capacitor then readily discharges it through a voltage reduction circuit to power vehicle accessories.

How does this affect collision repair?
The capacitor is located behind the front bumper on the left side. Given this placement the capacitor may require R&I even in smaller collisions to repair other damaged areas. The capacitor holds high-energy up to 25,000 joules,2896The vehicle should never be started without the capacitor in place.which may cause serious harm to servicing personnel or to the vehicle itself. Before removing the capacitor or touching any of the high-energy i-ELOOP connections, a service plug disconnect must be utilized. This will prevent shock or electrocution and the possibility of fire. If the capacitor is replaced, the damaged one must be fully discharged before disposal, and then discarded in compliance with local e-Waste regulations. Before installing a new capacitor, a jumper wire that is used during transport to prevent static charge build-up must be removed. If the jumper wire is not removed it will create a short circuit to ground within the i-ELOOP system.

The i-ELOOP capacitor is a "wet type" capacitor, and must be stored upright to prevent electrolyte leaks, which will damage the capacitor. Also, never use a new or used capacitor that has been dropped or otherwise damaged.

Mazda provides i-ELOOP repair and handling procedures that can be accessed at, and click-on the link for the Capacitor Disposal Manual.

Can I drive the vehicle without the capacitor installed?
Due to the way the i-ELOOP capacitor is connected, it is NOT recommended to start or run the vehicle without the capacitor in place. Pushing the vehicle however will not charge the i-ELOOP capacitor; therefore pushing a collision-damaged vehicle around a repair facility is permitted.

What about the battery?
Even though the battery is 12 volt, it is specifically designed for use with the i-ELOOP system. It's designated as a Q85 type battery, and is currently only available through Mazda. When replacing an i-ELOOP equipped vehicle's battery, be sure to install the correct Q85 type battery.

There are special procedures for jump starting, disconnecting and charging the Q85 battery. An i-ELOOP equipped vehicle can be jump-started, but the vehicle must not be driven until an in-dash i-ELOOP warning display turns off. Before disconnecting an i-ELOOP equipped vehicle's battery, a "current sensor" must be disconnected from the negative terminal. Failure to first disconnect this sensor can cause false sensor readings and set diagnostic trouble codes (DTCs). When reconnecting the battery terminals, first connect the positive terminal, and then the negative terminal without the current sensor connected. Finally reconnect the current sensor to the negative terminal.

Due to the internal design of the Q85 battery, the battery cannot be successfully quick charged. Quick charging will also cause internal damage to the battery. If the battery needs to be recharged, it should be done outside the vehicle, battery caps removed, and in a pan containing 11/2 - 2" of water to prevent battery overheating. Mazda Service Information provides complete and precise Q85 battery testing and recharging procedures that should be followed to guarantee proper battery service.

Can the bake cycle damage the capacitor or the battery?
The durability temperature of the i-ELOOP capacitor and Q85 battery is 185°F (85°C). Placing an i-ELOOP equipped vehicle in a properly used spraybooth will have no adverse effect on the i-ELOOP capacitor or Q85 battery.

Even though this system is not classified as a hybrid there are special considerations that must be addressed to keep everyone safe and the vehicle operating correctly. For complete repair information on the Mazda i-ELOOP system go to:

Mazda i-eLOOP components and parts descriptions Courtesy of Mazda North America Operations

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