I'm looking at two different relays to control a 55 amp inverter and I'm wondering what the value is with such a huge price difference. The only difference I see is the $65 relay has a control signal of 4 to 32 Vdc whereas the vehicle relay control input is 12v.
I can use another smaller relay to send 12v dc to the vehicle relay... I'm using an Arduino to control everything - output voltage of 5v.
One is a regular 12v 60 amp relay for a vehicle $5.19: Amazon
And the other is an Omega solid state SSRL240DC75 that's $65 Omega
The inverter is 1000w continuous power - 55amp max draw.
The vehicle relay is not mains rated, it only handles 12V load, ie 0.72kW. It is a purely mechanical device.
The SSR is for a mains load and controls many 10's of kW. It has a zero-crossing detector circuit
integral to the unit, and can only control AC mains, not DC.
Yes, if you believe the specs. But, you'll need a relay driver circuit to drive the 12V relay coil. Even if you find a similar 60A relay with a 5V coil, you'll probably need a driver circuit to supply the required coil current.
It seems small & cheap for a 60A relay, and the "specs" say "60A coil capacity", whatever that means... The relay coil doesn't take 60A, so it's hard to trust anything they say. And, there's no link to the datasheet. It may be fine, but I wouldn't be too surprised if it doesn't last too long...
I know there are 24v vehicles packed with relays isn't the 12v rating for the control voltage?
The coil and contacts are (apparently) both 12V. That's typical for automotive relays. 12V is probably the most common relay coil voltage, but you can find a wide range of coil & contact ratings.
And the other is an Omega solid state SSRL240DC75 that's $65 Omega
That particular SSR won't work because it's designed to switch AC. Most electrical-mechanical relays can switch either AC or DC, but solid state relays are different. Most AC SSRs use a TRIAC, and a TRIAC won't shut off until the current drops to zero (at the AC zero-crossing). There are DC solid state relays.
Solid state relays tend to be more expensive than regular electro-mechanical relays, but you can find SSRs that can be driven directly by the Arduino so you don't need a driver circuit. And, you'll pay a little more because Omega is a well-known reputable supplier and you can find the detailed specs, etc.
DVDdoug:
Solid state relays tend to be more expensive than regular electro-mechanical relays, but you can find SSRs that can be driven directly by the Arduino so you don't need a driver circuit. And, you'll pay a little more because Omega is a well-known reputable supplier and you can find the detailed specs, etc.
Could someone point me in the right direction for a relay that will work?
This is a mechanical relay and will waste ~1A just to keep the coil energized. Any auto store should stock them. As an aside, in the automotive world they like to call big relays "solenoids".
To wire it up the big power cable (battery positive) goes through the big bolts and the coil connections are the smaller posts. Typically you'd just use a light duty switch to energize the coil, but if you're trying to interface it with an Arduino or something you can just get a second relay (e.g. www.amazon.com/dp/B00P7QDJD2) for that. If you get the polarity wrong on the smaller posts it won't make a "clunk" noise; just reverse it if so.