Solid state relays

[JRouche]

My first post here to the electrical forum.

I am wiring up my air ride system and need some help. I usually use the standard "box" type mechanical relays for everything, they work great and hold up. But my custom panel Im making has a very limited amount of space.

So I was thinking about using some solid state relays. I have a few on hand. And they are good for 40amps. I only need to pull a max of 20 amps each.

I have used them alot on some CNC machine conversions and they fit the bill.

So.. Any reason you guys think they are not a proper use? They are alot lower in profile so that helps me alot.

So whatcha think? Doable? Any reason to NOT use them? Thanks ahead of time. I appreciate any advice. JR

[TnBlkC230WZ]

As long as they will hold up to the heat and vibration, I don't see why not. They usually mount in a denser foot print. There is also a miniturized micro relay out now that is half the size of a micro relay They are only available in SPST configurations and I think they are rated at 20 or 30 amps. I've never used one, but I have seen them.

[JRouche]

As long as they will hold up to the heat and vibration, I don't see why not. They usually mount in a denser foot print. There is also a miniturized micro relay out now that is half the size of a micro relay They are only available in SPST configurations and I think they are rated at 20 or 30 amps. I've never used one, but I have seen them.

Thanks for the reply. I dont see heat buildup as an issue. On the car it will only cycle once every so often, just to fill the tank or top it off. And as far as heat due to current draw I still think its within specs. Im only pulling 20amps max through the relay that is spec'ed out for 40amps.

I guess I kinda wanted to know why the solid state relays are not used for our cars. I use them some in my machines in the home shop. They work great. Nice tight package. Seems to be perfect for the cars that want a nice clean setup. And to be honest, old fashioned mechanical relays just sound kinda well, old.

A solid state relay just seems to me to be a better relay.

Id love to hear the problems with using them. Before I commit to wiring the car up.

Thanks for your input!! I always like to hear about the other folks ideas. JR

[TnBlkC230WZ]

The only real issue I could think of is the electrical system in a car is very noisy. Lots of ringing and voltage spikes and sags. Keeping them electrically close to the battery should help.