Avionics Master Relay

[Rallylancer122]

Hi All,

I'd like to install a relay to activate my avionics buss. I have about 40 amps on the buss, and that's too much to run through the rocker switch I have. (I'm rehabbing my Dad's -8, and it already has nice engrave rocker switches, otherwise I'd just replace the switch.)

Can anyone recommend a suitable, aviation grade relay?

Thanks,
DEM

[Mike S]

Check with B and C.

IIRC, that is where I got mine.

40A seems pretty high.............

[j-red]

You could just use an additional standard relay such as most of us have as our master. I wonder what you have on that bus: 40a seems like a bunch for even older avionics!

[John Tierney]

I'm using a standard Cube relay from the local auto parts store.

[Sam Buchanan]

Originally Posted by j-red

You could just use an additional standard relay such as most of us have as our master. I wonder what you have on that bus: 40a seems like a bunch for even older avionics!

Biggggggg sub-woofers!

[tim2542]

Check your load calcs, 40 amps seems way high, like by a factor of 4 or more. If so you can simplify and add lightness with a simple quality switch and dump the relay.
Tim Andres

[RONSIM]

AFS5600T, Dynon D10A, Dynon 120, GTN 650, GNS 430, TT 385, TXP 327, PM800BT, iFly 740, NavworxEXP..

Using heavy duty toggle switch(s).

Ron

[Nova RV]

Stein sells a prefabricated avionics bus with relay, I have one in my build
http://www.steinair.com/product/avio...elay-assembly/

It says 30 amps though so if your 40 amp estimate is correct, never mind

[vic syracuse]

Originally Posted by RONSIM

AFS5600T, Dynon D10A, Dynon 120, GTN 650, GNS 430, TT 385, TXP 327, PM800BT, iFly 740, NavworxEXP..

Using heavy duty toggle switch(s).

Ron

You have about 20 amps max here steady state while in flight and everything running on this bus. Stein's avionics bus will work, as will just using another master relay from Van's, Spruce, or B&C. Don't forget to put the diodes on the relay to protect the equipment.

Vic

[Carl Froehlich]

There are many relays that fit the bill. I use four of these:https://www.alliedelec.com/schneider...d-12/70185034/

I look for silver contacts and coil rating. I run #10 wires from each battery to each relay, the relay?s contacts wired in parallel. There is a primary Avionics #1 relay on the left battery as well as a primary Avionics #2 relay on right battery. There is also an ?Alternate? feed relay on each battery (Avionics #1 on the right battery and Aviionics #2 on the left battery). These relays operate independent of each battery?s master solenoid.

I strongly recommend you not use a single relay to feed your avionics. This is, but definition, designing in a single failure point that will leave you with a dark panel. See if you can split your panel into Nav #1, Comm #1, Nav #2, Comm #2 and so forth to divide the loads between Avionics #1 and Avionics #2.

Carl