Relay Noise

[vinter93]

Hello everyone!
I'm doing a project in my car where I have those kind of courtesy lights on your feet when you open the doors.
To achieve this I used a relay, the switch to turn the relay on is the lights on the roof and the power for the LEDs comes from a piggyback fuse from the fuse box.
With this the LEDs turn on when I open the doors and turn off when I close them, it works perfectly.
The only problem is the amount of buzzing the relay makes when turning on or off.
Sounds like a spring touching metal.
I don't know if this is relevant but the roof lights that serve as a switch, when I open the door, they have somewhat of a dimming, they don't turn on instantly, they dimm from off to fully bright in a couple of seconds instead of instantly.
Could this be the problem, because I'm not feeding 12v instantly to the relay and the step from 0 to 12v causes this?
Thanks in advance

 

[vinter93]

Update: I'm thinking on removing the relay and wire the LEDs directly to the roof lights.
So, I was using the roof lights as a switch to the relay and powering the LEDs from the piggyback fuse of the door switches because it can handle 30A and I thought it would be safer since the roof lights fuse is rated for 15A..
But after some calculations (4 roof bulbs of 5W each) + the LEDs would be safe to use on the roof wiring since it is rated for 15A. According to my calculations I would still have around 11A spare on the wiring.
Please correct me if I'm saying anything very stupid, I'm not an electrician, I just have a vague idea on how stuff works.
So 5W X 4 for the bulbs + 20W for the led strips and controller would be 40W.
40W ÷ 12V = 3.33A draw.
Now for the real question.
Is it safe to power the LEDs from the roof lightning wiring or everything I said makes no sense and I'm missing something?
I would fuse the positive wire just in case.
Thanks

 

[Megawatt]

Update: I'm thinking on removing the relay and wire the LEDs directly to the roof lights.
So, I was using the roof lights as a switch to the relay and powering the LEDs from the piggyback fuse of the door switches because it can handle 30A and I thought it would be safer since the roof lights fuse is rated for 15A..
But after some calculations (4 roof bulbs of 5W each) + the LEDs would be safe to use on the roof wiring since it is rated for 15A. According to my calculations I would still have around 11A spare on the wiring.
Please correct me if I'm saying anything very stupid, I'm not an electrician, I just have a vague idea on how stuff works.
So 5W X 4 for the bulbs + 20W for the led strips and controller would be 40W.
40W ÷ 12V = 3.33A draw.
Now for the real question.
Is it safe to power the LEDs from the roof lightning wiring or everything I said makes no sense and I'm missing something?
I would fuse the positive wire just in case.
Thanks

Vintner I was going to tell you that it had to much load on it. Relay contacts are generally good for 10 amps and DC is worse

 

[vinter93]

Vintner I was going to tell you that it had to much load on it. Relay contacts are generally good for 10 amps and DC is worse

Sorry, didn't get what you meant by that.
Are you saying that the relay causes too much load? Would it be better with the LEDs connected straight to the bulbs wiring?
EDIT: I'm using a relay rated for 40amps, if that's relevant

 

[dmxtothemax]

if your worried about the physical noise of mechanical relays ?
Then stop using mechanical relays,
Instead use solid state relays,
No noise at all.

 

[vinter93]

if your worried about the physical noise of mechanical relays ?
Then stop using mechanical relays,
Instead use solid state relays,
No noise at all.

I wasn't aware of the existence of those relays.
Is it the exact same function?

 

[Megawatt]

Sorry, didn't get what you meant by that.
Are you saying that the relay causes too much load? Would it be better with the LEDs connected straight to the bulbs wiring?
EDIT: I'm using a relay rated for 40amps, if that's relevant

If I was you I would connect them to the bulbs wiring and maybe add a switch

 

[vinter93]

If I was you I would connect them to the bulbs wiring and maybe add a switch

Yeah I'm going to do that. I'll add a fuse and a switch just in case.
I'll also swap the halogen bulbs for LEDs, that should lower the load on the wiring.
Thanks for the replies
[automerge]1580100270[/automerge]

Yeah I'm going to do that. I'll add a fuse and a switch just in case.
I'll also swap the halogen bulbs for LEDs, that should lower the load on the wiring.
Thanks for the replies

Can I wire the LEDs directly to one of the bulbs terminals or do I need to wire it to the dome switch?
I have easy access to the bulb terminals, it would make my life easier.

 

[Marvo]

You're using the roof light supply to switch the relay, the roof light is supplied via a dimmer which is why the relay is noisy when it switches off. The dimmer will cause it to buzz or chatter.

Connecting your new LED lights directly to the roof lights will almost certainly overload the dimmer unless you remove the lamps/bulbs from the roof lights first.

 

[vinter93]

You're using the roof light supply to switch the relay, the roof light is supplied via a dimmer which is why the relay is noisy when it switches off. The dimmer will cause it to buzz or chatter.

Connecting your new LED lights directly to the roof lights will almost certainly overload the dimmer unless you remove the lamps/bulbs from the roof lights first.

Yeah I suspected that the dimming was causing the relay noise...
So what would you recommend to do in my case?
[automerge]1580132538[/automerge]

Yeah I suspected that the dimming was causing the relay noise...
So what would you recommend to do in my case?

Maybe I can activate the relay directly from the door sensor instead of the roof bulbs.
Only problem is that I don't know how to access it or even how it looks like or where it connects..
I suppose it would give me 12v instantaneously and eliminate the buzzing correct?