Recommend a solid-state relay

[DrRoughneck]

Can you recommend a suitable solid-state relay. This is to replace a normal electro-mechanical relay driving a automotive horn.
Solid state relay needs to operate under 12V DC and sustain up to 45 amps. No AC requirements, it's for a horn.

 

[tom slick]

Why an SSR for a horn?

 

[Olas]

Like he said, ^, why an SSR for a horn? I use a standard 4 pin 40amp relay to drive two horns, one high and one low.
What do you hope to gain with SSR?

 

[DrRoughneck]

Originally Posted By: tom slick
Why an SSR for a horn?



Reliability. Previous electro mechanical relay died.

 

[Olas]

10 of your American Dollars...

https://www.sparkfun.com/products/13015

 

[DrRoughneck]

Originally Posted By: Olas
10 of your American Dollars...

https://www.sparkfun.com/products/13015

This one has an AC control voltage, I need DC.

 

[Johnny2Bad]

Punch in your specs at Mouser or Digikey.

I agree the standard mechanical "Bosch Type" relays work fine. The problem is there are cheap versions sold everywhere but if you buy genuine Bosch, TE, or Omron, they last forever. You want silver plated contacts for long life.

 

[Olas]

Originally Posted By: DrRoughneck
Originally Posted By: Olas
10 of your American Dollars...

https://www.sparkfun.com/products/13015

This one has an AC control voltage, I need DC.


Apologies. I found that link at 5am..

 

[SwampSurvivor]

How often are you using the horn that you wore out the relay?

 

[supton]

Yeepers. I looked at Digikey and they're not cheap. I have to wonder if using a pair of auto relays in parallel would work better. That and a back EMF diode across the contacts, in case you have an inductive load and it's the arcing that is causing relay damage.

I'd be tempted to make my own, especially if I could do low side switching. I started typing up thoughts but realized I was doing low side, which may not work for you.

 

[ironman_gq]

I'd just buy a brand name 40a relay and install a relay socket and have a spare relay in the glove box. Cheap, simple and largely reliable if you start with good components. Keep the relay out of areas where it can get soaked down, most aren't potted and water inside will kill them. For a good SSR you could be spending $80-100

 

[qjohn]

You could go on ebay and search for a F3LB-2C013-AA (Ford SSR). Buy one with the connector included.

It is rated at 20A continuous, and should be able to handle the peak current of a horn. It will shutdown if you try to push 40A continuous.

 

[HerrStig]

Solid state relays have some good points but the the junctions in the switching transistor(s) have to able to handle the spike produced when an inductive load circuit opens. Most horns are "linear motors" with a coil to move the horn diaphragm.

 

[JetStar]

Originally Posted By: DrRoughneck
Originally Posted By: tom slick
Why an SSR for a horn?



Reliability. Previous electro mechanical relay died.


What was the failure mode, open coil, shorted coil, open or stuck contacts? How many have you failed?
Enemies of relays are vibration, corrosion / contamination and of course proper application.
As others have said above, stick with a good brand name.

 

[brave sir robin]

I have had good luck by simply squirting a fair amount of pb blaster inside of relays. Did it recently with the fog light relay on my pathfinder and its been working like new ever since.

Pb blaster is excellent on corroded electrical parts. It cleans it well and keeps connections protected almost invisibly.

 

[tom slick]

To answer your original question I'd look at InPower
http://www.inpowerdirect.com/productfamilies.php

 

[dk1604]

Originally Posted By: HerrStig
Solid state relays have some good points but the the junctions in the switching transistor(s) have to able to handle the spike produced when an inductive load circuit opens. Most horns are "linear motors" with a coil to move the horn diaphragm.


A bit of a late response but HerrStig raises a very good point regarding inductive loads and relays. Now I don't know anything about how horns are made but if they don't have an integrated "freewheel" or flyback diode, and if you haven't already added one, then you'll definitely want one to protect the relay contacts when it opens. Without that freewheel diode you can kill or shorten the life of any relay regardless of it being mechanical or solid-state.

 

[meep]

Seems like you could ohm out the switched contacts pretty easily (ohmmeter needs adequate forward voltage or diode test mode) to detect the presence of a flyback diode.

I've never seen a horn with integrated diode or smoothing cap.

-m