Switching Automotive Relay Coil with Ekrano GX Relay | Flyback Risks

DIY
, , , ,
1

Greetings All,

Please assist.

Note: relates to 12VDC side of system.

Possible Impact On:

Ekrano GX Relay

Orion XS 1400 Remote H Terminal

Bosch Part No.: 0 986 AH0 453

Coil: 16 Ohms

Unit has resistor across Pin 85 & 86 for a level of flyback protection.

Questions for my benefit (thank you) but also for the benefit of others as this info isn’t too well documented online for Victron installers / users :

1. Is built in resistor sufficient flyback protection for Ekrano relay contacts or should it be diode protected?

2. If diode is necessary is it fine to add diode across terminals (of same relay) externally as suitable diode protected option is hard to come by where I am based.

3. If elsewhere in the system the Remote H terminals on Orion XS 1400’s are subjected to this particular relay’s flyback voltage, are those inputs prone to failing (again is diode protection necessary).

Thank you!

2

Hi, some relay sockets come with built-in interference-suppression modules (R-C networks) or, for DC applications, combinations of a diode and resistor.

Do you happen to have the part number for the relay socket?

It may make sense to fit the diode directly to the relay being switched using intermediate plugs, or to solder it onto the relay socket, or crimp it together with the cable terminals. There are several options to consider. Do you have any photos of the site?

3

Check whether the Bosch relay has a flyback diode. An external diode is fine by me.

The Bosch relay’s switch-off voltage may destroy the electronics upstream of it.