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Can I wire a relay delay module to be more effecient on standby Answered

I made a timed light powered from a usb powerbank, and a 5v relay delay module (like this https://encrypted-tbn0.gstatic.com/images?q=tbn:AN... ), I powered the module and the light (switched on by the module) in parallel from the powerbank, then ran a momentary switch from trigger to negative. Press the button and it switches on the light for a set interval (about 15 seconds in my case), so far so good.

The problem is that the powerbank (cheap and low capacity) runs down after a few days, primerily from the trickle of keeping the relay module ready for use.

Is there a simple way to stop the wasted current?


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2 years ago

Ok, after about one hour of trying to post a reply, text is finally appearing in the window :)

Waste is relative, as relative as your specs on the power supply or current draw.
One thing is certain though: If the relay is constantly on then you have a significant drop.
A transistor, like a cheap mosfet from the scrap box, a small SSR being creative could help.

For the creative part:
I assume your light is not really using much juice, maby even just a small LED.
You could check on the relay, datasheet or measure the current the relay needs to stay energised.
Wouldn't be surprised if your light needs about the same....
So with a suitable resistor to get to the voltage the relay you could just replace it with your light.
If it needs much more you might need to replace the transistor powering the relay with something bigger.