12V Coil Relay Continuous Clicking

[alnesbitt]

I seem to have an issue with this

This setup works correctly (see attached diagram) in that

1) The electronic controller supplies 12V at the relay cradle if above under voltage setting, and
2) on under voltage state, I get 0V at the relay cradle, and
3) The electronic controller resets when above over voltage setting to supply 12V at the relay cradle

PROBLEM

As soon as I add 12V coil relay continuous clicking .....WHY, why, why?

Further Clarification

If the electronic controller is above the under voltage setting the 12V relay does latch, but when the state of the electronic controller changes to undervoltage I get the continuous clicking

[relec]

Add a 12v bulb or similar to the relay and see if it is still doing that.

Might be that the controller is load sensitive and switches itself off if the current draw on the load side is not enough to prevent unnecessary drain from the battery.

[Richard Mackay]

Nice drawing!
Do you have a multi meter which you can use to measure the current that energises the relay coil?

[cainslie]

A continuous clicking relay is often a result of the relay drawing more current than the supply can source.

Similar to a clicking starter motor. In the case of a starter motor, the solenoid pulls some current and energizes the motor. The motor starts to pull current and the battery can't keep up so the solenoid releases. Now the motor is turned off, but there's enough current for the solenoid and the process starts again.

So, check how much current your controller can source and how much current your relay draws.

[ekkekan]

Current drawn by the relay could be 50mA so the source battery (3X100Ah) should be able to provide it easily. Clicking relay could also be because the controller output circuit does not switch on over 8V.

I take it that there is no load on the relay that can pull the battery voltage down to cause the lower voltage?

[Fluffy]

The relay is doing slow PWM regulation. Very common.

EDIT - Just saw that it is not a regulator but a low cut-out.

[Dungbeetle]

The relay is doing slow PWM regulation. Very common.

The word "common" is the clue in Fluffy's cripto

[alnesbitt]

Add a 12v bulb or similar to the relay and see if it is still doing that.

Might be that the controller is load sensitive and switches itself off if the current draw on the load side is not enough to prevent unnecessary drain from the battery.

I added a 12v bulb to the relay cradle supply (coil terminals), and it worked the issue now is that the bulb will be permanently illuminated while the electronic controller is in the "use battery state" (that is voltage is greater than "under voltage load stop") and thus will use the battery...adding to the amps already required to keep the 12v coil in the latched position and drain the battery further.

The reason for the latched position of the coil is that N/O contacts (12 Volt coil relay) provides a switch to another circuit which must only activate if there is sufficient battery capacity, thus in "Under Voltage load stop" no power from the Electronic controller the coil is de-energised and the other circuit stops

I think I will have to live with it....unless some other suggestion,

QUESTION: if I used a contactor instead of a relay or a solid state relay...would it solve the issue of having the 12v bulb permanently on?

Regards

[RussellF]

what are the "load start" and "load stop" settings?

sounds as if these are too close to each other ... when the load is removed from a battery, its voltage recovers/increases which then again triggers "load start". once load is reapplied the battery voltage drops to below "load stop".

[cainslie]

A continuous clicking relay is often a result of the relay drawing more current than the supply can source.

Similar to a clicking starter motor. In the case of a starter motor, the solenoid pulls some current and energizes the motor. The motor starts to pull current and the battery can't keep up so the solenoid releases. Now the motor is turned off, but there's enough current for the solenoid and the process starts again.

So, check how much current your controller can source and how much current your relay draws.

I'm wrong. Looking at pictures of the internals, the load is switched with a relay internally and it's rated to 20A.

I did find the attached though - looks like it doesn't like the load to be a relay. No idea why.

[alnesbitt]

what are the "load start" and "load stop" settings?

sounds as if these are too close to each other ... when the load is removed from a battery, its voltage recovers/increases which then again triggers "load start". once load is reapplied the battery voltage drops to below "load stop".

I have checked during testing ....and made sure they are way apart 12.8 stop...restart 15.5v

[alnesbitt]

I'm wrong. Looking at pictures of the internals, the load is switched with a relay internally and it's rated to 20A.

I did find the attached though - looks like it doesn't like the load to be a relay. No idea why.

Dammit.....the "fine print"

[cainslie]

Dammit.....the "fine print"

What are you powering off that relay?

The device itself can handle a 20A load (so it says) which is pretty substantial. You may be able to connect the load directly to that output without your relay.

[alnesbitt]

Dammit.....the "fine print"

Would a contactor or a solid state relay work?

[alnesbitt]

What are you powering off that relay?

The device itself can handle a 20A load (so it says) which is pretty substantial. You may be able to connect the load directly to that output without your relay.

Not powering anything off the relay...it is just a on/off contact or switch (zero volts over the N/O contacts, using one set of the N/O contacts to break the control circuit of the "other circuit") and the other circuit load would be too high to power through the electronic controller

[RussellF]

Not powering anything off the relay...it is just a on/off contact or switch (zero volts over the N/O contacts, and only using one set and cannot have 12 volts running through the switch) and the other circuit load would be too high to power through the electronic controller

https://www.robotics.org.za/YX-X0001-1

would be great to know what triggers the on/off chatter in the controller so that loads in excess of 20A can be switched ... my guess is that it could only be the back EMF from the external relay / solenoid - notwithstanding the fact there is no back EMF when ext relay switches on.

if possible and you're so inclined, try the following :

across the ext relay coils add a 100nF or so capacitor

post back if any change in the ext relay chatter freq

[Fluffy]

https://www.robotics.org.za/YX-X0001-1

would be great to know what triggers the on/off chatter in the controller so that loads in excess of 20A can be switched ... my guess is that it could only be the back EMF from the external relay / solenoid - notwithstanding the fact there is no back EMF when ext relay switches on.

if possible and you're so inclined, try the following :

across the ext relay coils add a 100nF or so capacitor

post back if any change in the ext relay chatter freq

Lower and upper set points too close too each other.

As it switches off the current drops and the battery voltage rises switching back on.

Repeat until dustbin time.

[alnesbitt]

https://www.robotics.org.za/YX-X0001-1

would be great to know what triggers the on/off chatter in the controller so that loads in excess of 20A can be switched ... my guess is that it could only be the back EMF from the external relay / solenoid - notwithstanding the fact there is no back EMF when ext relay switches on.

if possible and you're so inclined, try the following :

across the ext relay coils add a 100nF or so capacitor

post back if any change in the ext relay chatter freq

I will give it a go "ext relay coils"...more colour please

[alnesbitt]

Lower and upper set points too close too each other.

As it switches off the current drops and the battery voltage rises switching back on.

Repeat until dustbin time.

I have checked during testing ....and made sure they are way apart 12.8 stop...restart 15.5v (and it does now work if I attach a 12v bulb to the coil terminals of the cradle)

[ekkekan]

I will give it a go "ext relay coils"...more colour please

It just means the relay is not on the PC board but externally what you call a relay cradle.

I would say you can even use a larger capacitor like a 10uF as it doesn't matter if the relay stays in a few seconds longer.

What size 12V bulb did you use?

I just saw now cainslie showed a picture that the module needs a load larger than the 240ohm of the relay coil.