12V Coil Relay Continuous Clicking

[alnesbitt]

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.

5 watt bulb

[RussellF]

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)

... so the added 12V lamp attenuates the ext relay coil emf.

you could leave the lamp in place, but there is no guarantee of no future misbehaviour even with the lamp.

better fixes would be to :

one diode anode from "load +", cathode to "battery +" in the attached.

second diode anode from "load -", cathode to "battery -"

add 100nF or so capacitor across ext relay coil (ideally a ceramic capacitor which is better for high risetime spikes)

a much better solution is to add a zener / transzorb directly across the ext relay coil - suitably rated for ext relay / solenoid size and max battery voltage.

ideally the fix lies inside the controller circuitry but that would mean taking a closer look at its internals.