Looking for help on how to wire a relay

Question

Below is a picture of a relay I purchased. I want to use it to turn my inverter (connected to a 12v battery, provides 220 to a pump) on and off.

Unless you have a better idea, I think I should wire it into the inverter on/off switch somehow, but I am not sure what to wire to which terminal.

Secondly there are two terminals on the back of the inverter for the 12V battery cables. I assume that I should connect those to the two wires on the clip marked 12v. Do I just do that via some extra wires connecting from one to the other?

Help with how to wire this super appreciated.

dougw · Answer

This is a simple way to implement the hysteresis function you want. This circuit takes a higher battery voltage to turn power on to the inverter than to turn power off. It is not clear at what voltage the coil turns off - you will need to experiment. If the circuit is turning off at too low of a voltage, add more diodes in series with D4 until it turns off at the voltage you want. You will need to figure out which screw terminal to connect to the inverter - it will be C or D in colporteur diagram above. The relay switch input will be A in that diagram. The coil connections are marked DC 12V in your image. (Red is +)

shabaz · Answer

Hi Beatrice, The simplest way in this situation is to just apply 12V DC to the red and black wires, and you'll hear a click. You can use a multimeter set to 'ohms' or to 'continuity' and 'buzz out' the connections. You'll find that one of the two screw terminals on the left, will only make an electrical connection with one of the two screw terminals on the right, when 12V is applied to the red and black wires. Or, you can try to follow the traces on the underside, and the relay will be wired such that the two terminals are in a 'double pole single throw' configuration, or 'single pole single throw' with two screw terminals hard-wired together. Your multimeter is your best friend though. If you don't have one, they cost less than $5 sometimes. But in the interim, you could try to follow the traces if you don't have a multimeter. Once you have determined which two screw terminals get connected together only when 12V is applied to the red/black wires, then you can attach those screw terminals in series with the inverter on/off switch that you mention. The red and black wires will connect to whatever you wish to use to control the relay.

colporteur · Answer

Rather difficult to identify operation of the relay from the picture. Can you translate the details from the relay and/or a name for the module? Typically you would have a normally open (N.O.), common (COM), normally close (N.C.) contacts. C is connected to N.C. without power. When the relay is triggered C is then connected to N.O. You only have two wire connections. The relay is either going to make the circuit or break the circuit. The relay could be configured to switch the Input side power to the output side power when the relay is engaged.

jw0752 · Answer

Hi Beatrice,

If you have access to the On-Off power switch of the inverter it may not be a high current circuit. Many inverters will internally use a low current circuit to switch the higher power circuit on and off. If this is a case you may not need a relay to turn the inverter on and off, just a regular switch. If you feel that you need the 30 Amp contacts of the relay here is a suggested circuit hookup that you can use.

Sorry the picture got flipped on it's side.

John

Looking for help on how to wire a relay

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