Automatic Relay E-772

Intelligent relay E-772 V2

Reference: SRA102

VAT included

Intelligent relay E-772 V2


Intelligent relay E-772 V2

The new E772V2 is an evolution of the E-772 relay but incorporates an ideal diode motion and function sensor. With this relay, a fast and complete charging of the second battery in EURO6 vehicles with intelligent alternators is ensured. The new E772V2 relay also works with older vehicles.

The assembly of the E772V2 is simple, identical to the traditional E-772.

The intelligent relay E-772 V2 is the solution for EURO6 vehicles, many installers have opted so far to put booster, but it is an expensive solution both product and installation and consumes constantly once installed (higher consumption of gas). Others have used a relay piloted with D + but never get to charge the second battery at 100% (when the alternator lowers the voltage, the second battery is discharged towards the main).

In all equipped vehicles, an auxiliary battery is used so that when stopped, the consumption of
Do not exhaust the starter battery. The separating relay allows the auxiliary battery to be connected to the starting one
when the vehicle is running, for the alternator to charge the auxiliary battery, but isolates it when
It's stopped. Traditionally the alternators delivered voltages> = 13,4V constantly and with the
E772 traditional relay (V1) that voltage was detected to connect and disconnect.
With the entry into force of the low emission EURO6 regulations, car manufacturers have
developed alternators that offer a variable voltage depending on the need for consumption. The
new alternators help to consume less, but slows down the charge of a possible battery
assistant. The traditional relay E772 (V1) with the new alternators, sometimes will not connect or will take
more time to load depending on how the alternator behaves and the type of travel.
The new E772V2 smart relay has been designed to work with all alternators, including
the new ones. Installed in a vehicle with traditional alternator will work the same as relay E772 (V1)
but installed in a vehicle with intelligent alternator, it will allow to load more quickly.
Functions of the E772V2 relay:
• Function equivalent to the traditional E772. Connection> = 13,4V
• Motion detection. Use a motion sensor to deduce that the vehicle is in
March. A microcontroller processes the signal to rule out punctual vibrations and only give
by valid patterns that correspond to the vehicle in motion. There is a normal delay between
the motion detection system and the connection / disconnection of the relay.
• Ideal diode function. It has a sensor for the microcontroller to read the direction of the
current. This function prevents the starter motor from consuming the second battery and over
everything, that when the intelligent alternator does not offer voltage, the auxiliary battery is discharged
towards the main one. This function is basic with the new alternators, otherwise the battery
auxiliary would never be charged 100%. For this reason, it is not recommended to use standard relays
with key contact connection for vehicles with intelligent alternators.
• Main battery protection function. The relay separates the second battery if the main one is
less than 12V in any situation.
• It allows a peak current 180A and nominal current 120A.
Assembly and use advice:
• Use a cable section greater than or equal to 10mm2 and as short as possible. A lower section
and a long wiring would generate voltage losses that would confuse the microcontroller.
• Install the relay as close to the alternator as possible.
• Fix the relay jointly to the vehicle.
• If applicable, cancel the Start / Stop function of your vehicle when you need to load the
Second battery quickly.
• In the event that you load the vehicle on a boat or train, take the precaution of turning off all
Auxiliary battery charges.


Specific References